Occurrences of Mosasaur and other reptilian fossil remains from the Fox Hills Formation (Maastrichtian: late Cretaceous) of North Dakota
Available from
Myron Getman's profile on Mendeley.
Page 1
Occurrences of Mosasaur and other reptilian fossil remains from the Fox Hills Formation (Maastrichtian: late Cretaceous) of North Dakota
OCCURRENCES OF MOSASAUR AND OTHER REPTILIAN FOSSIL
REMAINS FROM THE FOX HILLS FORMATION
MAASTRICHTIAN: LATE CRETACEOUS! OF NORTH DAKOTA
By Myron R.C. Getman
A Bachelors Thesis submitted to the Faculty
of the Department of Geology of
St. Lawrence University
In partial fulfillment of the requirements for
the degree of
Bachelor of Science with Honors in Geology
Canton, N.Y.
1994
REMAINS FROM THE FOX HILLS FORMATION
MAASTRICHTIAN: LATE CRETACEOUS! OF NORTH DAKOTA
By Myron R.C. Getman
A Bachelors Thesis submitted to the Faculty
of the Department of Geology of
St. Lawrence University
In partial fulfillment of the requirements for
the degree of
Bachelor of Science with Honors in Geology
Canton, N.Y.
1994
Page 2
This thesis submitted by
in partial fulfillment of the requirements for the degree of
Bachelor of Science with Honors in Geology from the St.
Lawrence University is hereby approved by th faculty
advisor under whom the work was done.
te
in partial fulfillment of the requirements for the degree of
Bachelor of Science with Honors in Geology from the St.
Lawrence University is hereby approved by th faculty
advisor under whom the work was done.
te
Page 3
page
Title Page
Approval
Table of Contents
List of Pigures
'ist of Abbreviations
Acknowledgments
Abstract
Introducti.on
Methods
1V
V11
V111
Previous Works
Ages and Locat ons
Stratigraphic Descriptions
Systematic Paleontology
Summary
References
18
20
33
59
61
TABLE OF CONTENTS
Title Page
Approval
Table of Contents
List of Pigures
'ist of Abbreviations
Acknowledgments
Abstract
Introducti.on
Methods
1V
V11
V111
Previous Works
Ages and Locat ons
Stratigraphic Descriptions
Systematic Paleontology
Summary
References
18
20
33
59
61
TABLE OF CONTENTS
Page 4
nr' T ov Frcunms
pa
25Stratigraphic Column of Site A1050
2. Strati graphi c Correlation ofSites I, 2, and
31050
."igure 3. Stratigraphic Column showing Iron
Lightning/Fox Hills contact Carpenter et al. 1988! 32
Figure 4. Mosasaurus dekayi, buccal side and base of
tooth 35
Frgure 5. Mosasaurus dekayi, lin al side and tzp of
36tooth
Frgure 6. Mosasauzus dekayi, side v ews of tooth
showrng longitudinal carznae 37
Figure 7. Mosasaurus dekayi, illust ation of known
38specrmen Russell, 199gj
Figure 8. Plaoplatecarpus sp., buccal sade and top of
tooth
Figure 9. Plaoplatecarpus sp., lingual side and base of
tooth
Figure 10. Pli oplatecarpus sp., side views of tooth
showing very faint longitudinal carrnae
Figure 11. Mosasaur vertebra
F gure 12. Mosasaur vertebra
Figure 13. Iaedyosuchus sp., side vzew anti base of
tooth
Fzgure 14, Iaedyosuchus sp., anterror vrew a..d tip of
tooth
V
pa
25Stratigraphic Column of Site A1050
2. Strati graphi c Correlation ofSites I, 2, and
31050
."igure 3. Stratigraphic Column showing Iron
Lightning/Fox Hills contact Carpenter et al. 1988! 32
Figure 4. Mosasaurus dekayi, buccal side and base of
tooth 35
Frgure 5. Mosasaurus dekayi, lin al side and tzp of
36tooth
Frgure 6. Mosasauzus dekayi, side v ews of tooth
showrng longitudinal carznae 37
Figure 7. Mosasaurus dekayi, illust ation of known
38specrmen Russell, 199gj
Figure 8. Plaoplatecarpus sp., buccal sade and top of
tooth
Figure 9. Plaoplatecarpus sp., lingual side and base of
tooth
Figure 10. Pli oplatecarpus sp., side views of tooth
showing very faint longitudinal carrnae
Figure 11. Mosasaur vertebra
F gure 12. Mosasaur vertebra
Figure 13. Iaedyosuchus sp., side vzew anti base of
tooth
Fzgure 14, Iaedyosuchus sp., anterror vrew a..d tip of
tooth
V
Page 5
:.. g" e 15. Basilemys sp., dermal scute
Fig.re 16. Tyrannosaurid tooth fragment
Figure 17. Reptilian metacarpal fragment
Figure 18. Reptilian skull ?! fragment
Frgure 19. Reptilian metacarpal5355
58
Fig.re 16. Tyrannosaurid tooth fragment
Figure 17. Reptilian metacarpal fragment
Figure 18. Reptilian skull ?! fragment
Frgure 19. Reptilian metacarpal5355
58
Page 6
LIST OF ABBREVIATIONS
.Kansas StateKS..
.North Dakota Geological SurveyNDGS.
St. Lawrence UniversitySLU.
.Kansas StateKS..
.North Dakota Geological SurveyNDGS.
St. Lawrence UniversitySLU.
Page 7
ACKNOWLEDGMENTS
aid o the following people, this
:basis would not be possible: Dr. J. Mark
his rmmeasurable patience, knowledge, and
onal drive; Dr. John Hoganson ⬠for
finding most of the material used in the
fcr '. s enthusiasm, respect and ability to
s rings"; Peter Connett ⬠for being a constant
cos.panion anc partner during the field -session, for
being patient, open minded, and being able to tolerate
mv oddities; Dean Schwartz and the Office of Academic
Affairs ⬠for giving Peter and I the arants we needed to
complete our work and for being patient; Dr. F.D. "Bud"
Holland Jr. ⬠for heine a well sprinc of knowledge and
considerable aid in the field; Ray are Kathy Haas ⬠for
allowing Peter and 1 to stay at their home and for
giving us much needed breaks from orr work birding and
the Laird outcrop!; rhe Rotary Club of Glens Falls, NYâ¬
without whom most of my educational a..d thesis-related
financial needs would never have beer met, my family who
have supported me throughout this experier ce, and the
countless others who have helped in ays ti ey may not
realize.
aid o the following people, this
:basis would not be possible: Dr. J. Mark
his rmmeasurable patience, knowledge, and
onal drive; Dr. John Hoganson ⬠for
finding most of the material used in the
fcr '. s enthusiasm, respect and ability to
s rings"; Peter Connett ⬠for being a constant
cos.panion anc partner during the field -session, for
being patient, open minded, and being able to tolerate
mv oddities; Dean Schwartz and the Office of Academic
Affairs ⬠for giving Peter and I the arants we needed to
complete our work and for being patient; Dr. F.D. "Bud"
Holland Jr. ⬠for heine a well sprinc of knowledge and
considerable aid in the field; Ray are Kathy Haas ⬠for
allowing Peter and 1 to stay at their home and for
giving us much needed breaks from orr work birding and
the Laird outcrop!; rhe Rotary Club of Glens Falls, NYâ¬
without whom most of my educational a..d thesis-related
financial needs would never have beer met, my family who
have supported me throughout this experier ce, and the
countless others who have helped in ays ti ey may not
realize.
Page 8
Occurrences of Mosasaur and Other Reptilian fossil
remains from the Fox Hills Formation
Maastrichtian: Late Cretaceous! of North Dakota
Myron R.C. Hetman
ABSTRACT
In an attempt to add to the undezstancii..g of the
vertebrate biota of the Fox Halls Fozma ion of rhe Upper
Cretaceous !Maastrichtian! of North Dako a, three teeth and
a dermal scute recovered from the Timbe Lake/Iron Lightning
boundary of the Fox Hills Formation by R.M. Feldmann near
Linton, Emmons County were identified. Basec on morphology,
the larger of the two has been identified a Mosasaurus
dekayi Bronn 1838. The smoother tooth exhibits the conzcal,
nearly circular horizontal cross-sectio c .aracteristics
associated with crocodilian teeth. The smallest of the
teeth actually a tooth fragment! has been identified as
belonging to some type of Tyrannosaurid. The dermal scute
has been identified as belonging to the terrestrial turtle
Baszlemys sp.
A small tooth, a metacarpal and a verteoza were
zdentified. The tooth has been identified as belonging to
Plioplatecazpus sp. and the metacarpal be'ongs to an
unidentified reptile. The vertebra has been identzfied as
belongzng to a mosasaur.
remains from the Fox Hills Formation
Maastrichtian: Late Cretaceous! of North Dakota
Myron R.C. Hetman
ABSTRACT
In an attempt to add to the undezstancii..g of the
vertebrate biota of the Fox Halls Fozma ion of rhe Upper
Cretaceous !Maastrichtian! of North Dako a, three teeth and
a dermal scute recovered from the Timbe Lake/Iron Lightning
boundary of the Fox Hills Formation by R.M. Feldmann near
Linton, Emmons County were identified. Basec on morphology,
the larger of the two has been identified a Mosasaurus
dekayi Bronn 1838. The smoother tooth exhibits the conzcal,
nearly circular horizontal cross-sectio c .aracteristics
associated with crocodilian teeth. The smallest of the
teeth actually a tooth fragment! has been identified as
belonging to some type of Tyrannosaurid. The dermal scute
has been identified as belonging to the terrestrial turtle
Baszlemys sp.
A small tooth, a metacarpal and a verteoza were
zdentified. The tooth has been identified as belonging to
Plioplatecazpus sp. and the metacarpal be'ongs to an
unidentified reptile. The vertebra has been identzfied as
belongzng to a mosasaur.
Page 9
ddrtron, field work was performed during 1993. A
=-'te '." : a Timber Lake Member of the Fox Hills Formation
' as '= := ' in Bowman County, North Dakota whrch, after
exo'cr=- ","*, excavation and considerable sievrng produced
ma erial and, based on a broken metacarpal, is
thought to possibly belong to some type of turtle. The bone
belongs o two drstinct types, a compact "structural" type,
thought to be rib material, and a thinner, more porous type
believed to be a portion of the skull. During the field
sessron, a bone was also discovered within a concretion in
Emmons County. After cleaning and inspection, this bone has
been identified as a mosasaur vertebra.
The discovery of these vertebrate fossils aids in the
understandrng of the little studied Fox Hills reptilian
faunas. All the fossils, with the exception of Basi lemys
sp. are previously known in the Fox Hills Formatron.
Basilemys sp. is known from the Fox Hills of South Dakota
but not from North Dakota. An unrdentified mosasaur tooth
was repo ted by A.G. Leonard in the 1912 Hnited States
Geological Survey Bismark F'olio. At this time, the location
of the tooth is unknown.
The presence of Mosasaurus dekayi in the Fox Hills
represents a stratiaraphic and geographic range extension.
The Pli oplatecarpus sp., because it species is uncertain
may epresent a stratrgraphic range exten io from the
Campanran age Frerre Shale of South Dakota. cr a geographic
exent o.. From the Maastrichtian of New ersey. Two
=-'te '." : a Timber Lake Member of the Fox Hills Formation
' as '= := ' in Bowman County, North Dakota whrch, after
exo'cr=- ","*, excavation and considerable sievrng produced
ma erial and, based on a broken metacarpal, is
thought to possibly belong to some type of turtle. The bone
belongs o two drstinct types, a compact "structural" type,
thought to be rib material, and a thinner, more porous type
believed to be a portion of the skull. During the field
sessron, a bone was also discovered within a concretion in
Emmons County. After cleaning and inspection, this bone has
been identified as a mosasaur vertebra.
The discovery of these vertebrate fossils aids in the
understandrng of the little studied Fox Hills reptilian
faunas. All the fossils, with the exception of Basi lemys
sp. are previously known in the Fox Hills Formatron.
Basilemys sp. is known from the Fox Hills of South Dakota
but not from North Dakota. An unrdentified mosasaur tooth
was repo ted by A.G. Leonard in the 1912 Hnited States
Geological Survey Bismark F'olio. At this time, the location
of the tooth is unknown.
The presence of Mosasaurus dekayi in the Fox Hills
represents a stratiaraphic and geographic range extension.
The Pli oplatecarpus sp., because it species is uncertain
may epresent a stratrgraphic range exten io from the
Campanran age Frerre Shale of South Dakota. cr a geographic
exent o.. From the Maastrichtian of New ersey. Two
Page 11
INTRODUCTION
rs known about the reptilran fossils which are
the stratigraphy of the Fox Hills Formation.
sert of creatures might be found contained within this
which is transitional between the marine sediments
the Pierre Shale with its mosasaurs and other marine
eptrles and the terrestrial deposits of the Hell Creek
Formation and its dinosaurs'? Could there have been
rosasaurs exploiting the deltaic, barrier island, and other
regresszve environments that the Fox Hills Formation
Erickson, 1992! represents? Could they have been swimming
in the shallow waters feeding on ammonites, fish or, like
killer whales and sharks today, chasing larger prey onto the
beach to be devoured. These creatures and their marine
brethren were highly adapted, undoubtedly capable of amazing
hunting abilities. Could there have been tyrannosaurs
hunting on the terrestrral portion of the delta? There is
no reason to believe both these creatures and their
associated faunas were not in the deltaic environment of the
Fox Hills Formation. Previously, little of their remains
have been found. Perhaps the envrronment, which would have
been rich wrth brologrcal activrty, of the Fox Hills was not
conducive for the creation of fossils or perhaps, people
nave not been lookrng or wrlling to take the rime to look in
the rroht places. As a result, the vertebrate faunas of the
Fox Hrll Fcrma ron have not been studiec as closely as
those r. .he Prer e Shale and Hell Creek Formatrons.
rs known about the reptilran fossils which are
the stratigraphy of the Fox Hills Formation.
sert of creatures might be found contained within this
which is transitional between the marine sediments
the Pierre Shale with its mosasaurs and other marine
eptrles and the terrestrial deposits of the Hell Creek
Formation and its dinosaurs'? Could there have been
rosasaurs exploiting the deltaic, barrier island, and other
regresszve environments that the Fox Hills Formation
Erickson, 1992! represents? Could they have been swimming
in the shallow waters feeding on ammonites, fish or, like
killer whales and sharks today, chasing larger prey onto the
beach to be devoured. These creatures and their marine
brethren were highly adapted, undoubtedly capable of amazing
hunting abilities. Could there have been tyrannosaurs
hunting on the terrestrral portion of the delta? There is
no reason to believe both these creatures and their
associated faunas were not in the deltaic environment of the
Fox Hills Formation. Previously, little of their remains
have been found. Perhaps the envrronment, which would have
been rich wrth brologrcal activrty, of the Fox Hills was not
conducive for the creation of fossils or perhaps, people
nave not been lookrng or wrlling to take the rime to look in
the rroht places. As a result, the vertebrate faunas of the
Fox Hrll Fcrma ron have not been studiec as closely as
those r. .he Prer e Shale and Hell Creek Formatrons.
Page 15
was packed through to find any preces of
=:fter all the shipped material had been wet sreved and
eked through, the bone was examined for any matches wrth
otner pieces of bone. If any matches were found, the pieces
were carefully glued together. The bone material was then
examined.
The bone contained within the concretion found was
carefully cracked free from its confinement. Unfortunately,
some material was lost from the bone as a result of the
cracking of the very hard concretion. Next, excess
concretronary material was cut away with the use of a dremel
tool and a dramond blade. The bone was then examined.
Fortunately, the teeth, scute, and metacarpal required
no cleaning or preparation or wher already ed. They
were carefuliy examrned for any distinguishing features
which may be used for their proper identification. This
process was greatly aided by drawing illustrations and
careful measurement.
=:fter all the shipped material had been wet sreved and
eked through, the bone was examined for any matches wrth
otner pieces of bone. If any matches were found, the pieces
were carefully glued together. The bone material was then
examined.
The bone contained within the concretion found was
carefully cracked free from its confinement. Unfortunately,
some material was lost from the bone as a result of the
cracking of the very hard concretion. Next, excess
concretronary material was cut away with the use of a dremel
tool and a dramond blade. The bone was then examined.
Fortunately, the teeth, scute, and metacarpal required
no cleaning or preparation or wher already ed. They
were carefuliy examrned for any distinguishing features
which may be used for their proper identification. This
process was greatly aided by drawing illustrations and
careful measurement.
Page 18
was - crocodrle, and Adrien Camper shared
rha- ir. was a lizard. It would be ten year
818! reexaminatron of the Maastrrcht
rhe frrst mosasaur would be discovered rn
Ncrrc .=.:..aries zn the Cretaceous of New Jersey by Mitchrll
1967!. Mitchill correctly recognized hrs fossil
bern similar to the Maastricht mosasaur Russell, 1967!.
Mosasaurs were platynotan lizards and had evolved from
=:. "'"" e Cretaceous aigialosaurs, whrch were varanoids that
s' are many similar cranial characteristics with mosasaurs
our. rhezr post-cranial morphology was more similar to the
Varanus lrzards which are alive today rn Australia and
Africa Russell, 1967! ⬠"The skull is nearly, in every
respect, of the pattern of the Varanidae...," Baur, 1890!,
The Varanidae and Mosasauridae both have an articulatzng
joint in the middle of their rami Baur, '890!. "Among the
diverse irving groups rncluded in the I acertilia, mosasaurs
resemble the varanids or monitor lizards most closely, a
fact that has been generally recognized since the beginning
of the nrneteenth century," Russell, 1964, p. I!.
The varanids are a very old group of reptrles ⬠going
back at least to the Jurassic Williston, 1904!. The
d sccverv of Arazalosauridae and Dolrchosauridae in the
early la er Cretaceous of England and Yugoslavia helped
develop a mos- =- r nd lizard assocrarion b cause they both
possesse- vararorc characteristrcs Russe'I, 1967!. Osborn
decided tha mc =- azrs could not have e -o ved from
rha- ir. was a lizard. It would be ten year
818! reexaminatron of the Maastrrcht
rhe frrst mosasaur would be discovered rn
Ncrrc .=.:..aries zn the Cretaceous of New Jersey by Mitchrll
1967!. Mitchill correctly recognized hrs fossil
bern similar to the Maastricht mosasaur Russell, 1967!.
Mosasaurs were platynotan lizards and had evolved from
=:. "'"" e Cretaceous aigialosaurs, whrch were varanoids that
s' are many similar cranial characteristics with mosasaurs
our. rhezr post-cranial morphology was more similar to the
Varanus lrzards which are alive today rn Australia and
Africa Russell, 1967! ⬠"The skull is nearly, in every
respect, of the pattern of the Varanidae...," Baur, 1890!,
The Varanidae and Mosasauridae both have an articulatzng
joint in the middle of their rami Baur, '890!. "Among the
diverse irving groups rncluded in the I acertilia, mosasaurs
resemble the varanids or monitor lizards most closely, a
fact that has been generally recognized since the beginning
of the nrneteenth century," Russell, 1964, p. I!.
The varanids are a very old group of reptrles ⬠going
back at least to the Jurassic Williston, 1904!. The
d sccverv of Arazalosauridae and Dolrchosauridae in the
early la er Cretaceous of England and Yugoslavia helped
develop a mos- =- r nd lizard assocrarion b cause they both
possesse- vararorc characteristrcs Russe'I, 1967!. Osborn
decided tha mc =- azrs could not have e -o ved from
Page 19
dclichcsaurs '" cause of the greater numbe of cervical
the dolichosaurs Russell, 1967!
icicnall v, ihe aigialosaurs, opeti.osaurs, and mosasaurs
'iffer from the moni.tora in that they have seven ~ertebrae
in their necks ⬠a characteristic no othez reptiles posses
Williston, 1904!. The aigialosaurs, to strengthen the
case, have all the intermediate traits whi.ch link the
mosasaurs to the monitors Williston, 1914!.
Ncsasaurs belong to the Order Souamata, which is
described as: "A single, upper temporal vacuity, or,
secondarily none; quadrate loosely articulated with cranium;
teeth on palate; intercentra more or less persistent; a
single coracoid; ribs single-headed, central," Williston,
1914, p. 17!. One very distinguishing feature of this
Order, which makes up a majority of all 1'ving reptiles, is
its members have overlapping dermal scales Williston,
1914!. Osborn, after studying the mosasaurs, decided that
mosasaurs were an ancient offshoot of the Lacertilia
Russell, 1967!. The Lacertilia are described as
possessir,g: "Continuity of the parietal and sphenoid walls
interrupted. Rami of the mandible united by suture," Cope,
1864, p. 224!. "Ancestral mosasaur" seem to have been of
two basic ypes; forms with long bodies and short dilated
tails giving zi.se to the mosasaurines, anci forms with short
bodies and iona pointed tails giving rise to the
plioplatecarpi. es and tylosaurines," Russo 1, 1967!.
the dolichosaurs Russell, 1967!
icicnall v, ihe aigialosaurs, opeti.osaurs, and mosasaurs
'iffer from the moni.tora in that they have seven ~ertebrae
in their necks ⬠a characteristic no othez reptiles posses
Williston, 1904!. The aigialosaurs, to strengthen the
case, have all the intermediate traits whi.ch link the
mosasaurs to the monitors Williston, 1914!.
Ncsasaurs belong to the Order Souamata, which is
described as: "A single, upper temporal vacuity, or,
secondarily none; quadrate loosely articulated with cranium;
teeth on palate; intercentra more or less persistent; a
single coracoid; ribs single-headed, central," Williston,
1914, p. 17!. One very distinguishing feature of this
Order, which makes up a majority of all 1'ving reptiles, is
its members have overlapping dermal scales Williston,
1914!. Osborn, after studying the mosasaurs, decided that
mosasaurs were an ancient offshoot of the Lacertilia
Russell, 1967!. The Lacertilia are described as
possessir,g: "Continuity of the parietal and sphenoid walls
interrupted. Rami of the mandible united by suture," Cope,
1864, p. 224!. "Ancestral mosasaur" seem to have been of
two basic ypes; forms with long bodies and short dilated
tails giving zi.se to the mosasaurines, anci forms with short
bodies and iona pointed tails giving rise to the
plioplatecarpi. es and tylosaurines," Russo 1, 1967!.
Page 21
11
Cc- -ease, 322, .aurpnekepuhis Mehl, 1930, and tzodon Owen,
little is known about the osteology of the Trrbe
dansant Dollo, 1924! Russell, 1967. However, it rs
be eoarate from the Mosasaurinr due to its
sp' erical teeth Russell, 1967!. This tribe is
c" prised of the genus Globidens Gilmore, 1912. Russell
ibes the Tribe Plotosaurini as having, "More than
'''elve pygal vertebrae present. Radius and ulna nearly
contact above carpalia on distal border of antebrachial
fora..cn," Russell, 1967, p. 145!. Based on differences in
!.e ...anus, the Plotosaurini are separated in a unique trzbe
from the rest of the Mosasaurinae Russell, 1967!. The
Plotosaurrnr is composed of the genera us Camp,
1951, Compressidens Dollo, 1924, and Taniwhasaurus Hector,
1874.
Within the Plioplatecarpinae, the Tribe
Plioplatecarpinr Dollo, 1884! Russell, 1967, has a "Canal
through basrocczprtal and basisphenoid for basilar artery.
Delrcately proportioned jaws, teeth striated and subcircular
in cross-section. Chevrons free. These are generally
mosasaurs of moderate size, with relatively short jaws and
long, slender teeth," Russell, 1967, p. 148!. This tribe
is made cp of the genera Piatecarpus Cope, 1869,
:ctenos urus Merrian, 1894, and Piiopiatecarpus Dollo, 1882
Rus el', 1967!. The Prognathociontini Russell, 1967, has a
"Deep gros:e '..: oo of basroccrpital anc basrsphenoid for
hastier artery. Ma sivelv proportior ed jaws, teeth faceted
Cc- -ease, 322, .aurpnekepuhis Mehl, 1930, and tzodon Owen,
little is known about the osteology of the Trrbe
dansant Dollo, 1924! Russell, 1967. However, it rs
be eoarate from the Mosasaurinr due to its
sp' erical teeth Russell, 1967!. This tribe is
c" prised of the genus Globidens Gilmore, 1912. Russell
ibes the Tribe Plotosaurini as having, "More than
'''elve pygal vertebrae present. Radius and ulna nearly
contact above carpalia on distal border of antebrachial
fora..cn," Russell, 1967, p. 145!. Based on differences in
!.e ...anus, the Plotosaurini are separated in a unique trzbe
from the rest of the Mosasaurinae Russell, 1967!. The
Plotosaurrnr is composed of the genera us Camp,
1951, Compressidens Dollo, 1924, and Taniwhasaurus Hector,
1874.
Within the Plioplatecarpinae, the Tribe
Plioplatecarpinr Dollo, 1884! Russell, 1967, has a "Canal
through basrocczprtal and basisphenoid for basilar artery.
Delrcately proportioned jaws, teeth striated and subcircular
in cross-section. Chevrons free. These are generally
mosasaurs of moderate size, with relatively short jaws and
long, slender teeth," Russell, 1967, p. 148!. This tribe
is made cp of the genera Piatecarpus Cope, 1869,
:ctenos urus Merrian, 1894, and Piiopiatecarpus Dollo, 1882
Rus el', 1967!. The Prognathociontini Russell, 1967, has a
"Deep gros:e '..: oo of basroccrpital anc basrsphenoid for
hastier artery. Ma sivelv proportior ed jaws, teeth faceted
Page 22
12
='": ⬠-1 in cross section. Chevrons either
caudal centra," Russell, 1967, p. 162!
the Prognatodontini appear plioplatecarpine but
more massive and have correspondingly larger
R"ssell, 1967!. The Prognathodontini is composed
oenera Pzognathodon Dollo, 1889, and Plesdotylosaurus
1942 Russell, 1967!. There are some genera of the
Plioplatecarprnae which have an uncertain tribal affiliation
specifically, Halisaurus Marsh, 1869, and Dollosauzus
Takovlev, 1901. The subfamily Tylosaurinae is its own tribe
and is composed of the genera Tylosauzus Marsh, !872, an
Hainosauzus Dollo, 1885 Russell, 1967!. Theze are many
species of mosasaurs which have uncertain taxonomic
placement Russell, 1967! and this information can cause
confusion when studying the literature.
The Maastzicht mosasaur went unnamed for quite some
time. party-two years after its discovery, the fossil was
given the generic name Mosasaurus Russell, 1967!. Over the
years, the trzvzal name belgicus, camperz, giganteus, and
hoffmanni where also applied Russell, 1967!. Mantell, in
1828, determined that Mosasaurus hoffmanni was the earliest
name applied to the Maastricht mosasaur Russell, 1967!. As
a result, Mosasauzus hofrmanni Mante l 1828, became the
Mosasaurus genotype Pezsson, 1959!. in 1830, a mosasaur
was dzscovered zn the Missouri territory which was described
by Harlan and ".old uss and was named by Harlan as
Ichthyo eurus ...:ssourzensis Russell, 1967!. Later, t.hzs
='": ⬠-1 in cross section. Chevrons either
caudal centra," Russell, 1967, p. 162!
the Prognatodontini appear plioplatecarpine but
more massive and have correspondingly larger
R"ssell, 1967!. The Prognathodontini is composed
oenera Pzognathodon Dollo, 1889, and Plesdotylosaurus
1942 Russell, 1967!. There are some genera of the
Plioplatecarprnae which have an uncertain tribal affiliation
specifically, Halisaurus Marsh, 1869, and Dollosauzus
Takovlev, 1901. The subfamily Tylosaurinae is its own tribe
and is composed of the genera Tylosauzus Marsh, !872, an
Hainosauzus Dollo, 1885 Russell, 1967!. Theze are many
species of mosasaurs which have uncertain taxonomic
placement Russell, 1967! and this information can cause
confusion when studying the literature.
The Maastzicht mosasaur went unnamed for quite some
time. party-two years after its discovery, the fossil was
given the generic name Mosasaurus Russell, 1967!. Over the
years, the trzvzal name belgicus, camperz, giganteus, and
hoffmanni where also applied Russell, 1967!. Mantell, in
1828, determined that Mosasaurus hoffmanni was the earliest
name applied to the Maastricht mosasaur Russell, 1967!. As
a result, Mosasauzus hofrmanni Mante l 1828, became the
Mosasaurus genotype Pezsson, 1959!. in 1830, a mosasaur
was dzscovered zn the Missouri territory which was described
by Harlan and ".old uss and was named by Harlan as
Ichthyo eurus ...:ssourzensis Russell, 1967!. Later, t.hzs
Page 23
13
be changed to Mosasaurus missou iensis Russell,
:: e species Mosasaurus dekayi was esrabli.shed from a
ie cro n of a tooth from New Jersey Russell, 1967! and
ge us Ciidastes was established on a single dorsal⬠e r- which was found by Marsh in New Jersey Cope,
'868K!.
Mosasaurs were interesting and fz gl tening creatures.
Often, zheir nature of appearance h s spawned i.de s of sea
monsters existing in the pzesent day. 'Take, for example
:his passaae:
he sea serpents, or mosasaurs, grew to be as much as
40 feet long. They had scales like a s ake. Theirjaws also had hinges or oints, one t t e middle of
the chin and two at each side, whic allowed the mouth
to gape very widely, and to swallo very large
animals. On the other hand, unlike snakes, they
possessed small limbs in the form of ' ve f' ngered
flippers. It is interesting to note that these sea
serpents died out about he am tir:. that the living
coelacanth was previously thought to have become
extinct, so that it is hard to deny completely
thai.r possible existence in the sea roc!ay. Smith,1956!
Mosasaurs, which swam with axial sub-und ations of the
posterior portion of the body ⬠using their fl ppers and
neck for equilibrium and steering Lingham-Soli.ar, 1991!,
did look a lot like the sea serpents of lore but there is n
doubt they became extinct like the dinosaurs.
Although Marsh and Cope are c dited with proving
mosasaurs had flippers, a man named Herma n Schlegel 804-
1884! ','== he " : o make the d' cover; ..41 publish the
results ;N 'der ⬠.-.=' heunissen, lo86,'. Sc! egel, who was
be changed to Mosasaurus missou iensis Russell,
:: e species Mosasaurus dekayi was esrabli.shed from a
ie cro n of a tooth from New Jersey Russell, 1967! and
ge us Ciidastes was established on a single dorsal⬠e r- which was found by Marsh in New Jersey Cope,
'868K!.
Mosasaurs were interesting and fz gl tening creatures.
Often, zheir nature of appearance h s spawned i.de s of sea
monsters existing in the pzesent day. 'Take, for example
:his passaae:
he sea serpents, or mosasaurs, grew to be as much as
40 feet long. They had scales like a s ake. Theirjaws also had hinges or oints, one t t e middle of
the chin and two at each side, whic allowed the mouth
to gape very widely, and to swallo very large
animals. On the other hand, unlike snakes, they
possessed small limbs in the form of ' ve f' ngered
flippers. It is interesting to note that these sea
serpents died out about he am tir:. that the living
coelacanth was previously thought to have become
extinct, so that it is hard to deny completely
thai.r possible existence in the sea roc!ay. Smith,1956!
Mosasaurs, which swam with axial sub-und ations of the
posterior portion of the body ⬠using their fl ppers and
neck for equilibrium and steering Lingham-Soli.ar, 1991!,
did look a lot like the sea serpents of lore but there is n
doubt they became extinct like the dinosaurs.
Although Marsh and Cope are c dited with proving
mosasaurs had flippers, a man named Herma n Schlegel 804-
1884! ','== he " : o make the d' cover; ..41 publish the
results ;N 'der ⬠.-.=' heunissen, lo86,'. Sc! egel, who was
Page 24
o" the Rijksmuseum van Maturli7ke Historic in
sade the discovery in 1854 Nulder and Theunissen,
Rreviously, mosasaurs had been thought to have been
walk on land. Schlegel proved this theory incorrect
xam. ning the mosasaur phalanges and noticing a lack of
attachments for muscles or tendons ⬠the opposite of what is
see. in land animals Mulder and Theunissen, 1986!.
The cranium of a mosasaur is an interesting de~i.ce.
Cver the coarse of their evolution, the mosasaurian cranium
<as 'ell as their bodies! became more streamlined and their
.bs became more and more paddle-like Russell, 1964!. The
extra hinge i.n the lower jaw is a peculiar trait of the
mosasaurs and rheir relatives Aigialosaurus, Opeti.osaurus!
another characteristic not seen in any orher reptiles
Willi.stun, 1904!.
The lower jaw was doubly hinged in the back while the
front ends of the dentaries were locsely connected
with ligmental bonds. This adaptation of the skull
allowed the jaw to spread immensely and permitted the
predaceous and pugnaciousNosasaurs to swallow animals considerably larger in
diameter than themselves.
Sevon, 1957, p. 144!
Interestingly, mosasaur jaws are very similar to those in
Hesperornis and provide a provide a good case of convergent
evolution Gregory, 1951!. Mosasaurs, which were very
active predators, ate just about anything smaller than they
were and were a ded in feeding by "steptostylic quadrates
wh cn! per.. red anteroposterio movers. r of the
mandible ..." 8 'ss 1', 1967, p. 1!.
sade the discovery in 1854 Nulder and Theunissen,
Rreviously, mosasaurs had been thought to have been
walk on land. Schlegel proved this theory incorrect
xam. ning the mosasaur phalanges and noticing a lack of
attachments for muscles or tendons ⬠the opposite of what is
see. in land animals Mulder and Theunissen, 1986!.
The cranium of a mosasaur is an interesting de~i.ce.
Cver the coarse of their evolution, the mosasaurian cranium
<as 'ell as their bodies! became more streamlined and their
.bs became more and more paddle-like Russell, 1964!. The
extra hinge i.n the lower jaw is a peculiar trait of the
mosasaurs and rheir relatives Aigialosaurus, Opeti.osaurus!
another characteristic not seen in any orher reptiles
Willi.stun, 1904!.
The lower jaw was doubly hinged in the back while the
front ends of the dentaries were locsely connected
with ligmental bonds. This adaptation of the skull
allowed the jaw to spread immensely and permitted the
predaceous and pugnaciousNosasaurs to swallow animals considerably larger in
diameter than themselves.
Sevon, 1957, p. 144!
Interestingly, mosasaur jaws are very similar to those in
Hesperornis and provide a provide a good case of convergent
evolution Gregory, 1951!. Mosasaurs, which were very
active predators, ate just about anything smaller than they
were and were a ded in feeding by "steptostylic quadrates
wh cn! per.. red anteroposterio movers. r of the
mandible ..." 8 'ss 1', 1967, p. 1!.
Page 26
informatics, the Smoky Hill Member of the Nioorara
D rota was deposzted zn a quiet shallow
..nfav"rable conditions for bottom creatures Seven,
Cc-:.parazzve1y little rs known about immature
.-..osasau s and, although only a few young mosasaurs are known
d Sheldon, 1986! they are known from approximately
formations in the United States of America Sheldon,
1993!. It has been suggested that they lived in fresh water
specifzcally, rivers! and this might have had an influence
on thezr preservation Camp, 1942!.
Mosasaurs are known throughout the wozld. They are
known from Antarctica, Niger Lingham-Soliaz, 1991!,
England, Belgium, Russia, France, New Jersey, Georgia,
Alabama, Mississippi, Texas, New Mexico, Colorado, Kansas,
Nebraska, North Dakota, South Dakota, Nyomir g and other
localitres in the United States of America Williston, 1914,
Camp, 1942!. Unfortunately, most mosasaur material is not
very effective when used in a stratigraphic context due
crushed and fragmentary condrtion most are found in Camp,
1942!. It is known, however, that they only occur in the
Upper Cretaceous and that, "The earliest occur in beds of
Upper Cenomzan aqe rn Kent, where only fragmentary specimens
are known," Camp, 1942, p. 1!. Local genera of mosasaurs
are not wide-ranqing Camp, 1942! and this fact, no doubt,
!' as an znfluet ca on their effectzveness as a stratigraphrc
tool. Mosasaur =- . ssouruensis was found in "a hard bluish
gray lzmestone, he " th junctron of he Yellow-stone and
D rota was deposzted zn a quiet shallow
..nfav"rable conditions for bottom creatures Seven,
Cc-:.parazzve1y little rs known about immature
.-..osasau s and, although only a few young mosasaurs are known
d Sheldon, 1986! they are known from approximately
formations in the United States of America Sheldon,
1993!. It has been suggested that they lived in fresh water
specifzcally, rivers! and this might have had an influence
on thezr preservation Camp, 1942!.
Mosasaurs are known throughout the wozld. They are
known from Antarctica, Niger Lingham-Soliaz, 1991!,
England, Belgium, Russia, France, New Jersey, Georgia,
Alabama, Mississippi, Texas, New Mexico, Colorado, Kansas,
Nebraska, North Dakota, South Dakota, Nyomir g and other
localitres in the United States of America Williston, 1914,
Camp, 1942!. Unfortunately, most mosasaur material is not
very effective when used in a stratigraphic context due
crushed and fragmentary condrtion most are found in Camp,
1942!. It is known, however, that they only occur in the
Upper Cretaceous and that, "The earliest occur in beds of
Upper Cenomzan aqe rn Kent, where only fragmentary specimens
are known," Camp, 1942, p. 1!. Local genera of mosasaurs
are not wide-ranqing Camp, 1942! and this fact, no doubt,
!' as an znfluet ca on their effectzveness as a stratigraphrc
tool. Mosasaur =- . ssouruensis was found in "a hard bluish
gray lzmestone, he " th junctron of he Yellow-stone and
Page 30
21
c.:s, maroonish shale approximately 1 foot
th clayier lzthologies hrgher
;appz ximately 25 feet!
cement.ed, fine to medium grained, purple
sandstone which thine laterally.
:nourated, brown weathering, fine, laminated,
'azk brown, silty sandstone interpreted as
berng channel fall. Upper 1 foot
bentonitic/bentonite. Capped by Unit 6.
n'ndurated, buff weathering, fine to very fine,
ferrugineous, slightly resistent lamir ated,
25'+
0'5"
1'10"
0 lignaceous salty sandstone.
X3 Unrndurated, fine to very fine, uba..euler to
angular, buff weathering, orange-tan
1'0"
salty-clayey sandstone grading upward to
I greenish gray, laminated, micaceous,
31'
a=icy sancsro e with la ge scale t ougn cross
bed ' nc. Indurared un ts are lease' 5 in nature
silty-clayey sandstone. Pod of garosize ?l
observed 3 feet from top of the unit . arne
Ophiomorpha common on restricted hor'zona.
Large Ophiomorpha observed 25 feet frc. case of
the unrt. Topped by lignitic, laminated, silty
sandstone. Large Ophiomorpha sugge t onditions
becoming estuarine upward.
2* Indurated, frne to medium grained, suoangular,
b: =" weazherrng, micaceous, lamrnazed, an,
c.:s, maroonish shale approximately 1 foot
th clayier lzthologies hrgher
;appz ximately 25 feet!
cement.ed, fine to medium grained, purple
sandstone which thine laterally.
:nourated, brown weathering, fine, laminated,
'azk brown, silty sandstone interpreted as
berng channel fall. Upper 1 foot
bentonitic/bentonite. Capped by Unit 6.
n'ndurated, buff weathering, fine to very fine,
ferrugineous, slightly resistent lamir ated,
25'+
0'5"
1'10"
0 lignaceous salty sandstone.
X3 Unrndurated, fine to very fine, uba..euler to
angular, buff weathering, orange-tan
1'0"
salty-clayey sandstone grading upward to
I greenish gray, laminated, micaceous,
31'
a=icy sancsro e with la ge scale t ougn cross
bed ' nc. Indurared un ts are lease' 5 in nature
silty-clayey sandstone. Pod of garosize ?l
observed 3 feet from top of the unit . arne
Ophiomorpha common on restricted hor'zona.
Large Ophiomorpha observed 25 feet frc. case of
the unrt. Topped by lignitic, laminated, silty
sandstone. Large Ophiomorpha sugge t onditions
becoming estuarine upward.
2* Indurated, frne to medium grained, suoangular,
b: =" weazherrng, micaceous, lamrnazed, an,
Page 31
22
:=- ⬠'era lv ' o unindurated sands of a
co-,-osit'on. Occasional Ophiomorpha are
indurated unrt. Lower contact
3'1"
rated, fine to very fine, subangular to
buff weathering, tan, laminated,
silty-clayey sandstone. Small to
small Ophfomorpha are seen but are rare.
Un't g ades upward into Unit 2. 2'7"
65'total thickness
Note: The section begins at a knick point made by an
indurated ledge in the Timber Lake Member of the F'ox Hills
Formation. The base of the Fox Hills Formation is covered
by valley fill. Therefore, the entire thickness of the Fox
Hills has not been measured.
Section at Locality A1050
westward-facing gully on a large slump block with a small
stream incision, T. 130 N., R. 106 H., Sec. 24, Bowman
County, North Dakota.
Slump B ock N . ' Iyigures 1&2!
Fox Hrlls Fo=:.erron Thickness
:=- ⬠'era lv ' o unindurated sands of a
co-,-osit'on. Occasional Ophiomorpha are
indurated unrt. Lower contact
3'1"
rated, fine to very fine, subangular to
buff weathering, tan, laminated,
silty-clayey sandstone. Small to
small Ophfomorpha are seen but are rare.
Un't g ades upward into Unit 2. 2'7"
65'total thickness
Note: The section begins at a knick point made by an
indurated ledge in the Timber Lake Member of the F'ox Hills
Formation. The base of the Fox Hills Formation is covered
by valley fill. Therefore, the entire thickness of the Fox
Hills has not been measured.
Section at Locality A1050
westward-facing gully on a large slump block with a small
stream incision, T. 130 N., R. 106 H., Sec. 24, Bowman
County, North Dakota.
Slump B ock N . ' Iyigures 1&2!
Fox Hrlls Fo=:.erron Thickness
Page 32
23
feet and
inches!
ake Member
rated upwards
Unrndurated, buff-tan weathering, brown clay
lenses of sandstone and dark black! clay.
:o .er contact gradational.
Ur:ndurated, dark brown weatherina, da k
brown-black clay. Grades into Unrr 5.
3 Unrndurated, fine to very fine, angular to
subangular, buff weathering, tan, silty
sandstone. Presence of Ophiomorpha sug ested
by small piece of tunnel. Pods of 'arc ite ?!
observed
2 Unindurated, dark gray wearherinc, gray to black
1'3"
0'2.5"
0'3.5"
clay with popcornesgue weatberiru
characteristics. Thine larerall 0'0.5"
1 Unindurated, fine to verv fire, anc:lar to
subangular, buff we-=bering, an, '=-=..:.":.=":ed,
silty sandstone. 3'4.5"
5'9"total theet ess
Slump Block Mc. ". ;:- = = s 'a2!
rat-ci, buff weathering, dark gray clay 0'4"
incurs-ed, buff weathering, brown, sandy
one hfch becomes more clayey and
feet and
inches!
ake Member
rated upwards
Unrndurated, buff-tan weathering, brown clay
lenses of sandstone and dark black! clay.
:o .er contact gradational.
Ur:ndurated, dark brown weatherina, da k
brown-black clay. Grades into Unrr 5.
3 Unrndurated, fine to very fine, angular to
subangular, buff weathering, tan, silty
sandstone. Presence of Ophiomorpha sug ested
by small piece of tunnel. Pods of 'arc ite ?!
observed
2 Unindurated, dark gray wearherinc, gray to black
1'3"
0'2.5"
0'3.5"
clay with popcornesgue weatberiru
characteristics. Thine larerall 0'0.5"
1 Unindurated, fine to verv fire, anc:lar to
subangular, buff we-=bering, an, '=-=..:.":.=":ed,
silty sandstone. 3'4.5"
5'9"total theet ess
Slump Block Mc. ". ;:- = = s 'a2!
rat-ci, buff weathering, dark gray clay 0'4"
incurs-ed, buff weathering, brown, sandy
one hfch becomes more clayey and
Page 33
Thickness
!feet and
Laches!
5:lls Formation
Trmber Lake Member
' nit
23* Indurated, fine to very fine, buff weathering,
tan, micaceous, silty sandstone with
laminations and trough crossbedding. Lensoid
in nature and grading laterally into sands
with similar compositions and containing
Ophiomorpha no Ophiomorpha in indurated
portion!. Lower contact gradational.
22 Unindurated, fine to very fine, buff
weatherrnq, angular to subangular strongly
laminated, tan, silty-clayey sandstone with
lenses of light brown to dark brown clays,
grades upwards into unit 23.
21 Indurated, fine, brown weathering, purple Mn02
0'9"
Bt3
0'2.5"cemented sandstone
20 Unindurated, brown-buff weathering, dark brown
clay with lenses of silty sandstone
.5"-I" thick!.
19 Unindurated, fine to very fine, angular to
subangular, buff weathering, tan, strongly
1 .inated, arity sandstone with thi lenses of
0'3"
clay. Possible microchannel fall and5'ss le
1'2"user =-= on inoles observed
IB U. ' =.=-:=== "', bro- n-* -ff weatne" nc, da k brown
cl=-, "= ='=. -': ==- :ate ally ,''ensoi"' .n nature!.0'1"
!feet and
Laches!
5:lls Formation
Trmber Lake Member
' nit
23* Indurated, fine to very fine, buff weathering,
tan, micaceous, silty sandstone with
laminations and trough crossbedding. Lensoid
in nature and grading laterally into sands
with similar compositions and containing
Ophiomorpha no Ophiomorpha in indurated
portion!. Lower contact gradational.
22 Unindurated, fine to very fine, buff
weatherrnq, angular to subangular strongly
laminated, tan, silty-clayey sandstone with
lenses of light brown to dark brown clays,
grades upwards into unit 23.
21 Indurated, fine, brown weathering, purple Mn02
0'9"
Bt3
0'2.5"cemented sandstone
20 Unindurated, brown-buff weathering, dark brown
clay with lenses of silty sandstone
.5"-I" thick!.
19 Unindurated, fine to very fine, angular to
subangular, buff weathering, tan, strongly
1 .inated, arity sandstone with thi lenses of
0'3"
clay. Possible microchannel fall and5'ss le
1'2"user =-= on inoles observed
IB U. ' =.=-:=== "', bro- n-* -ff weatne" nc, da k brown
cl=-, "= ='=. -': ==- :ate ally ,''ensoi"' .n nature!.0'1"
Page 34
Fegu e 1.-- St ratzgrap'nic
Celur.e -: S te '= ".SS
T. 13
e 's
Se". 2-'l
Celur.e -: S te '= ".SS
T. 13
e 's
Se". 2-'l
Page 36
27
0'2"
rated, buff-brown weathering, brown-orange
-:'"-stone grading upwards into unindurated
silty clay. 0'5"
4 Unindurated, buff weathering, dark brown clay. 0'1.5"
3 Unindurated, fine to very fine, buff
weathering, orange-tan, silty-clayey sandstone.0'2.5"
2 Uz ndurated, fine to very fine, buff
weathering, dark gray clay. 0'l.5"
1 iJnindurated, fine to very fine, angular to
subangular, buff weathering, tan, silty
sandstone. Pods of jarosite ?! observed. 0'10"
total t..'' c.cn ss 9'3.5"
composrte total hick. ess 13'2"
Section at Locality 2
Cut bank of Seven sil reek cr.:but ="; consistsof aS uther.. ⬠s ="=:.-." - che ancinc l ck.
N., B. 106 N., Sec. 25
Foot Block Fio: re 2l
Thickness
feet and
0'2"
rated, buff-brown weathering, brown-orange
-:'"-stone grading upwards into unindurated
silty clay. 0'5"
4 Unindurated, buff weathering, dark brown clay. 0'1.5"
3 Unindurated, fine to very fine, buff
weathering, orange-tan, silty-clayey sandstone.0'2.5"
2 Uz ndurated, fine to very fine, buff
weathering, dark gray clay. 0'l.5"
1 iJnindurated, fine to very fine, angular to
subangular, buff weathering, tan, silty
sandstone. Pods of jarosite ?! observed. 0'10"
total t..'' c.cn ss 9'3.5"
composrte total hick. ess 13'2"
Section at Locality 2
Cut bank of Seven sil reek cr.:but ="; consistsof aS uther.. ⬠s ="=:.-." - che ancinc l ck.
N., B. 106 N., Sec. 25
Foot Block Fio: re 2l
Thickness
feet and
Page 37
rnches!
Sim'lar in texture and appearance to Unit 8 but
not indurated ⬠buff weathering, fine to very
fine, tan, silty sandstone, with lamrnations.
Trough crossbedding present. Outcrop capped by
valley fill.
8 Similar in texture and appearance to Unit 6â¬
buzf-brown weathering, but sand/clay
ir terbedding appears to occur in closer
8' ⬠10'
6'-7intervals.
14' 5"
tan-orange, laminated sandstone witl
interbeddings Mn08/clay layers. A possible
bentonite layer was observed. Grades upward
into sandstone of similar lithology wh'ch is
bioturbated and contains Ophi omorpha. Lo''er
contact gradatronal.
5 Unrnd rated, fane to very fine, buff weathering,
gr yish-tan, lamrnated, silty sandstone. Grades
0' ll"
1' 10"ento nrr 6.
7- Loosely indurated, fine to very fine, buff
weathering, lensoid, tan, silty sandstone which
grades laterally into unindurated sar detune with
the same lithology. Ophdomorpha and ' arge
crossbedding are present. Interfingers, in a
step-wise manne , with brown units Mn08 and
clayl 10" to 1' thick.
6 Unindurated, fine to very fine, buff weathering,
Sim'lar in texture and appearance to Unit 8 but
not indurated ⬠buff weathering, fine to very
fine, tan, silty sandstone, with lamrnations.
Trough crossbedding present. Outcrop capped by
valley fill.
8 Similar in texture and appearance to Unit 6â¬
buzf-brown weathering, but sand/clay
ir terbedding appears to occur in closer
8' ⬠10'
6'-7intervals.
14' 5"
tan-orange, laminated sandstone witl
interbeddings Mn08/clay layers. A possible
bentonite layer was observed. Grades upward
into sandstone of similar lithology wh'ch is
bioturbated and contains Ophi omorpha. Lo''er
contact gradatronal.
5 Unrnd rated, fane to very fine, buff weathering,
gr yish-tan, lamrnated, silty sandstone. Grades
0' ll"
1' 10"ento nrr 6.
7- Loosely indurated, fine to very fine, buff
weathering, lensoid, tan, silty sandstone which
grades laterally into unindurated sar detune with
the same lithology. Ophdomorpha and ' arge
crossbedding are present. Interfingers, in a
step-wise manne , with brown units Mn08 and
clayl 10" to 1' thick.
6 Unindurated, fine to very fine, buff weathering,
Page 38
29
:rated, fine to very fine, buff weathering,
;.: osseous, laminated, tan, silty sandstone whzch
.:=-=beds wath dark brown fissile clay layers 1
4 inches thick. Pods of jarosite ?!
obsezved. Capped by a 0.5" indurated, brown
weathering, fine to very fine, brown, silty
sandstone with Mn02.
3 Uninourated, fine to very fine, buff weathering,
laminated, tan to brown., silty sandstone with
nodules of dazk brown clay. Interbeddings of
clay become more common towards the top of the
unit.
0 I 3 5
7' 1"
1 Unindurated, fine to very fine, buff weathering,
laminated, tan, sandstone with interbeddings of
dark clay. Small pods of jarosite ! present.
Grades upward into a lensoid, indurared unit
with similar compositzon. Capped by Unit 2. 3' 8"
total thickness 53' 3.5"
Hanging Block Figure 2!
Pie re Shale
and
Thickness
!feet and
inches!
Fox Hills "or .atzo
Unit
2 Unindurated, brown weathering, dark brown clay. 0' 1"
:rated, fine to very fine, buff weathering,
;.: osseous, laminated, tan, silty sandstone whzch
.:=-=beds wath dark brown fissile clay layers 1
4 inches thick. Pods of jarosite ?!
obsezved. Capped by a 0.5" indurated, brown
weathering, fine to very fine, brown, silty
sandstone with Mn02.
3 Uninourated, fine to very fine, buff weathering,
laminated, tan to brown., silty sandstone with
nodules of dazk brown clay. Interbeddings of
clay become more common towards the top of the
unit.
0 I 3 5
7' 1"
1 Unindurated, fine to very fine, buff weathering,
laminated, tan, sandstone with interbeddings of
dark clay. Small pods of jarosite ! present.
Grades upward into a lensoid, indurared unit
with similar compositzon. Capped by Unit 2. 3' 8"
total thickness 53' 3.5"
Hanging Block Figure 2!
Pie re Shale
and
Thickness
!feet and
inches!
Fox Hills "or .atzo
Unit
2 Unindurated, brown weathering, dark brown clay. 0' 1"
Page 41
32
HELL CREEK FM.
LiN ON MBR
m
0
Ill
CL'
0u'X
0
LU
m
TRAIL CITY MBR
PIERRE SHALE
Figure 3. ⬠⬠Strat2.graphic Column showing ron Lightning/Fox
Ha.lls Ccntaci an ' s. atigraphrc level of si e OY3 T. 132
N., R. ,3 W., Sec. , Emmons County, .'""=.-. Dakota .
modif2ec frc.. Carcenier et a . '9SS'
0
IL
0
ZZ cs
'z I
0 g
Z~
0
0
Ul
UJ
m
0
Z
0
C
0
Ir
0
0
m
0
HELL CREEK FM.
LiN ON MBR
m
0
Ill
CL'
0u'X
0
LU
m
TRAIL CITY MBR
PIERRE SHALE
Figure 3. ⬠⬠Strat2.graphic Column showing ron Lightning/Fox
Ha.lls Ccntaci an ' s. atigraphrc level of si e OY3 T. 132
N., R. ,3 W., Sec. , Emmons County, .'""=.-. Dakota .
modif2ec frc.. Carcenier et a . '9SS'
0
IL
0
ZZ cs
'z I
0 g
Z~
0
0
Ul
UJ
m
0
Z
0
C
0
Ir
0
0
m
0
Page 43
0.4 cm, 0.3 cm, 0.4 cm, 0.4 cm, and 0 .5 cm. On
he buccal and lzngual sides, the facets are their
v szons begin to smooth closer to the tip until
approxzmately one third to one quarter of the tooth is
smooth and lacking facets.
Due to the size and curvatures of the lzngual and
buccal sides, the tooth is nearly triangular in cross
section. An examination of the base of the tooth Figure 4!
reveals a nerve cavity which is approximately 1 cm deep.
Discussion. ⬠⬠Based on the broken enamel and uneven nature
c rhe base, the marginal tooth has been interpreted as
having been lost before it could be replaced Figures 4,5 &
6!. The tooth zs posterzorily recurved and the tip is
broken off ⬠most probably due to wear. Using the number of
facets on the buccal and lingual side of the tooth and its
morphology and a diagram and description of a known 74.
dekayf Figure 7! Russell, 1994!, the tcoth has been
identified as Mosasaurus dekayi.
Stratzgraphzc Ievel ard Age.-- Thzs toot!. was collected
from the Timber Lake/Iron Lightning Member boundry of the
Fox Hills Formation. It is Maastrichtian in age.
CLASS Reptilia
SUBCLASS Lepidosauria
ORDER Squamata
he buccal and lzngual sides, the facets are their
v szons begin to smooth closer to the tip until
approxzmately one third to one quarter of the tooth is
smooth and lacking facets.
Due to the size and curvatures of the lzngual and
buccal sides, the tooth is nearly triangular in cross
section. An examination of the base of the tooth Figure 4!
reveals a nerve cavity which is approximately 1 cm deep.
Discussion. ⬠⬠Based on the broken enamel and uneven nature
c rhe base, the marginal tooth has been interpreted as
having been lost before it could be replaced Figures 4,5 &
6!. The tooth zs posterzorily recurved and the tip is
broken off ⬠most probably due to wear. Using the number of
facets on the buccal and lingual side of the tooth and its
morphology and a diagram and description of a known 74.
dekayf Figure 7! Russell, 1994!, the tcoth has been
identified as Mosasaurus dekayi.
Stratzgraphzc Ievel ard Age.-- Thzs toot!. was collected
from the Timber Lake/Iron Lightning Member boundry of the
Fox Hills Formation. It is Maastrichtian in age.
CLASS Reptilia
SUBCLASS Lepidosauria
ORDER Squamata
Page 44
Bigure -'..-- Mosasa "us dekayi, KS specznen, ite OY3. Scale
A. :- seal sade. B. Base o= tooth
A. :- seal sade. B. Base o= tooth
Page 45
Fig re . ⬠⬠Mosasaosus dekayi, KSspeczm ., zte OY3. Scal
ha" s cm. .'. :co=eel he. B. T pof tooth.
ha" s cm. .'. :co=eel he. B. T pof tooth.
Page 46
:rgure 6. ⬠⬠Mosasaurus deka',
BS specrmea, sate OY3. Scale bar
-s cru S de vre..s of the tooth
s..o' l..c 'o .o t"dr:al carrnae
A. B' ca t 'o t. B u c 1
to left
BS specrmea, sate OY3. Scale bar
-s cru S de vre..s of the tooth
s..o' l..c 'o .o t"dr:al carrnae
A. B' ca t 'o t. B u c 1
to left
Page 47
38
/
nisei ~
*5'- 8
Fsgure 7. ⬠Yc ese "us ceksyz, illustsu ' - . c: known
spec nen !tecec Fccc gussell, 1994!.
/
nisei ~
*5'- 8
Fsgure 7. ⬠Yc ese "us ceksyz, illustsu ' - . c: known
spec nen !tecec Fccc gussell, 1994!.
Page 48
SUBORDER Lac rtilia
FAMILY Mosasari dae Gervais 1853
SUBFAMILY Plioplatecarpinae Dollo 1884
TRIBE Plioplatecarpini Dollo 1884
GENUS Plioplatecarpus Dollo 1882
"Mandibular teeth bicarinate ?!, vertically striated and
medially recurved Dollo, 1882, p. 64; 1889b, pl. 10 fig.
14" Russell, 1967!.
Referred Specimen.-- NDGS specimen, szngle fragment of a
tooth collected by Dr. John Hoganson approximately one mile
north of site A1050.
Diagnosis and Description. ⬠⬠The tooth fragment is 1.4 cm
tall, 0.7 cm wide, and 0.5 cm thick Figures 8 & 9!. Two
longrtudznal carinae are faintly visible ',Figure 10!. The
tzp and base of the have been broken of ⬠probably due to
loss before replacement.
Discusszon. ⬠⬠The very small size of ti.e tooth makes
identzfzcation dzfficult. After rt was ciiscovered by John
Hoganson, it was taken to Dr. Gorden Be 1, Jr. who
identified it as belonging to the Genus " iopiatecazpus
Dollo 1882. It may belong to the species Plzopiatecarpus
primaveus Russell, 1967 which is known from the DeGrey
Member of the lower Pierre Shale of South Dakota Russell,
1967!. The rooth is nterpreted to have been broken, and
subsequently lost, d e to wear based on: he strarght break
FAMILY Mosasari dae Gervais 1853
SUBFAMILY Plioplatecarpinae Dollo 1884
TRIBE Plioplatecarpini Dollo 1884
GENUS Plioplatecarpus Dollo 1882
"Mandibular teeth bicarinate ?!, vertically striated and
medially recurved Dollo, 1882, p. 64; 1889b, pl. 10 fig.
14" Russell, 1967!.
Referred Specimen.-- NDGS specimen, szngle fragment of a
tooth collected by Dr. John Hoganson approximately one mile
north of site A1050.
Diagnosis and Description. ⬠⬠The tooth fragment is 1.4 cm
tall, 0.7 cm wide, and 0.5 cm thick Figures 8 & 9!. Two
longrtudznal carinae are faintly visible ',Figure 10!. The
tzp and base of the have been broken of ⬠probably due to
loss before replacement.
Discusszon. ⬠⬠The very small size of ti.e tooth makes
identzfzcation dzfficult. After rt was ciiscovered by John
Hoganson, it was taken to Dr. Gorden Be 1, Jr. who
identified it as belonging to the Genus " iopiatecazpus
Dollo 1882. It may belong to the species Plzopiatecarpus
primaveus Russell, 1967 which is known from the DeGrey
Member of the lower Pierre Shale of South Dakota Russell,
1967!. The rooth is nterpreted to have been broken, and
subsequently lost, d e to wear based on: he strarght break
Page 50
Figure 9. ⬠Blioplatecarpus sp., NDGS specimen, recov r d
approximately 1 mile from site A1050. Scale bar is 1 cm.
A. Langual s de. B. Base of tooth.
approximately 1 mile from site A1050. Scale bar is 1 cm.
A. Langual s de. B. Base of tooth.
Page 52
seen on the base of the specimen, the missing tap, and the
ex namely worn longrtudanal carrnae.
Stratigraphic level and Acre.-- This tooth was recovered
:rom the Timber Lake Member of the Fox Hills Formation, It
is Maastrichtian in age.
ORDER Sguamata
SUBORDER Lacertilia
FAMILY Mosasauridae Gervaas 1853
Re ar ed spacemen.-- SLU No. 1833, single vertebra.
Collected by J. Mark Erickson at A131, T. 128 N., R. 80 N.,
Sec. 6, Sroux County, North Dakota.
Diagnosis and Description. -- The vertebra is 2 cm wide 3 1
cm tall, and 2.3 cm thick. Both articu sting surfaces are
smooth and a slaghtly raised ridge may be seen on the upper
portion of the fossil fpz.gare ll!
Discussion.-- This vertebra was recovered from a
Dosiniopsis pod by J. Mark Erickson and 'dentified by Dr.
Gorden Bell Jr. as belongrng to some kind of a mosasaur.
Stratigraphic level and Age. -- The vertebra is from the
Timber Lake Member of the Fox Hills Formation and is
Maastrrchtian an age.
ORDER Sguamata
SUBORDER Lacertrlza
FAMILY Mosasauradae
ex namely worn longrtudanal carrnae.
Stratigraphic level and Acre.-- This tooth was recovered
:rom the Timber Lake Member of the Fox Hills Formation, It
is Maastrichtian in age.
ORDER Sguamata
SUBORDER Lacertilia
FAMILY Mosasauridae Gervaas 1853
Re ar ed spacemen.-- SLU No. 1833, single vertebra.
Collected by J. Mark Erickson at A131, T. 128 N., R. 80 N.,
Sec. 6, Sroux County, North Dakota.
Diagnosis and Description. -- The vertebra is 2 cm wide 3 1
cm tall, and 2.3 cm thick. Both articu sting surfaces are
smooth and a slaghtly raised ridge may be seen on the upper
portion of the fossil fpz.gare ll!
Discussion.-- This vertebra was recovered from a
Dosiniopsis pod by J. Mark Erickson and 'dentified by Dr.
Gorden Bell Jr. as belongrng to some kind of a mosasaur.
Stratigraphic level and Age. -- The vertebra is from the
Timber Lake Member of the Fox Hills Formation and is
Maastrrchtian an age.
ORDER Sguamata
SUBORDER Lacertrlza
FAMILY Mosasauradae
Page 53
I',g 'op.
Figure j'. ⬠⬠."..""= =': eertecra, S'g Yo. 1B33, srte A131
Scale bar
Figure j'. ⬠⬠."..""= =': eertecra, S'g Yo. 1B33, srte A131
Scale bar
Page 55
46
specimen. ⬠⬠SLU No. 1B34, single vertebra.
llected by J. Mark Erickson at the northeast corner of
i32 N., R. 78 W., Sec. 3, 9 miles west and I/2 mile north
of Linton, Emmons County, North Dakota.
Diagnosis and escript on.-- The ver ebra is 4.5 cm tall,
3.4 cm wide, and 3.9 cm thick fpigure 12!. It has a
somewhat pear-shaped cross section and has a raised edge
imilar to the previous vertebra.
'acus i on.-- This fossil has been identified as a mosasaur
based on its similar morphology with the previous vertebra
identified by Dr. Gorden Bell Jr. Unfortunately, this
vertebra is in not as good condition as the other because it
was damaged when the concretion it was in was cracked open.
The bone also appears to have been fairly worn previous to
its incorporation as the core for the concretion.
Apparently, the vertebra was free to roll around on the
ocean bottom for some time.
Stratigraphic Level and Age. ⬠⬠This vertebra was collected
from the upper Timber Lake Member of the Fox Hills
Formatron. It is Maastrrchtian in age.
INFRACIASS Archosauromorpha
SUPERORDER Archosauria
ORDER Crocodylia
SUBORDER Eosuchia
FAMILY Crocodylidae
SUBFAMILY Crocodylinae
specimen. ⬠⬠SLU No. 1B34, single vertebra.
llected by J. Mark Erickson at the northeast corner of
i32 N., R. 78 W., Sec. 3, 9 miles west and I/2 mile north
of Linton, Emmons County, North Dakota.
Diagnosis and escript on.-- The ver ebra is 4.5 cm tall,
3.4 cm wide, and 3.9 cm thick fpigure 12!. It has a
somewhat pear-shaped cross section and has a raised edge
imilar to the previous vertebra.
'acus i on.-- This fossil has been identified as a mosasaur
based on its similar morphology with the previous vertebra
identified by Dr. Gorden Bell Jr. Unfortunately, this
vertebra is in not as good condition as the other because it
was damaged when the concretion it was in was cracked open.
The bone also appears to have been fairly worn previous to
its incorporation as the core for the concretion.
Apparently, the vertebra was free to roll around on the
ocean bottom for some time.
Stratigraphic Level and Age. ⬠⬠This vertebra was collected
from the upper Timber Lake Member of the Fox Hills
Formatron. It is Maastrrchtian in age.
INFRACIASS Archosauromorpha
SUPERORDER Archosauria
ORDER Crocodylia
SUBORDER Eosuchia
FAMILY Crocodylidae
SUBFAMILY Crocodylinae
Page 56
Figure 13.-- Zl edpos" caus sp., KS spec'.-.. =, site OY3. Scale
bar is 1 cre A. -=- rae .. B. Base c: Got?.
bar is 1 cre A. -=- rae .. B. Base c: Got?.
Page 58
50
SUBCLASS Testudinata
ORDER Chelonia
SUBORDER Cryptodi ra
SUPERFAMILY Trionychozdae
FAMILY Dezmatemydzdae
GENUS Basiiemys Hay, 1902
"Shell highly sculptured. Epiplasrra much thickened.
Bridge wade. Intergular scutes present. Pectorals greatly
ex assed at the midline, narrowed laterally. An axillary
a c an ngu0nal scute but no other ir. ra,arginals....This
genu cif ers from other known genera o De matemydidiae in
havi a no inframarginals, except the axi lary and the
inguinal, " IHay, 1908! .
Referzed specimen.-- KS Specimen, cern scute collected by
R.M. Feldmannn at site OY3, T. 132 N., R. 78 N., Sec. 1,
Emmons County, North Dakota
Dzagnosis and Desc iption. -- The fr- c:e t is approximately
4.3 cm long, 2 cm wide, and 2 cm tall. It . ss a very
convoluted, bumpy surface and has twc ta 1, cone-shaped
uprazszngs with well defined tips IFzgu Sl. The bone is
fairly solid zn appearance and sturdy zn s zucture.
Di scr ss ~ on. ⬠⬠This piece was identizzed by Dz . John
Hoganson as bezng a dermal scute f o,. the e bow or knee of
sasi le...ys p. based on direct compari on ', th a speczmen
from the vzell '-''seu.... The two cone-1' ze sr zres with the
turtle's carapace, = astzon, and other scares, no doubt
SUBCLASS Testudinata
ORDER Chelonia
SUBORDER Cryptodi ra
SUPERFAMILY Trionychozdae
FAMILY Dezmatemydzdae
GENUS Basiiemys Hay, 1902
"Shell highly sculptured. Epiplasrra much thickened.
Bridge wade. Intergular scutes present. Pectorals greatly
ex assed at the midline, narrowed laterally. An axillary
a c an ngu0nal scute but no other ir. ra,arginals....This
genu cif ers from other known genera o De matemydidiae in
havi a no inframarginals, except the axi lary and the
inguinal, " IHay, 1908! .
Referzed specimen.-- KS Specimen, cern scute collected by
R.M. Feldmannn at site OY3, T. 132 N., R. 78 N., Sec. 1,
Emmons County, North Dakota
Dzagnosis and Desc iption. -- The fr- c:e t is approximately
4.3 cm long, 2 cm wide, and 2 cm tall. It . ss a very
convoluted, bumpy surface and has twc ta 1, cone-shaped
uprazszngs with well defined tips IFzgu Sl. The bone is
fairly solid zn appearance and sturdy zn s zucture.
Di scr ss ~ on. ⬠⬠This piece was identizzed by Dz . John
Hoganson as bezng a dermal scute f o,. the e bow or knee of
sasi le...ys p. based on direct compari on ', th a speczmen
from the vzell '-''seu.... The two cone-1' ze sr zres with the
turtle's carapace, = astzon, and other scares, no doubt
Page 59
Sl
Figure 13.-- Basilemys sp. dermal scute, KS specimen, site
QY3. Scale bar s - cm. A. Side view. B. Top view.
Figure 13.-- Basilemys sp. dermal scute, KS specimen, site
QY3. Scale bar s - cm. A. Side view. B. Top view.
Page 60
some: har efzective defense and protection from
the wears and rears of daily life.
* evel and Age. ⬠⬠This fragment was collected
z Lake/Iron Lightning Member contact in the
.ation. It is Maastrichtian in age.
CLASS Reptilia
SUBCLASS Archosauria
ORDER Saurischia
SUBORDER Theropodia
INFRAORDER Carnosauria
FAMILY Tyrannosauridae
Referred specimen.-- KS Specimen, tooth rragment collected
by R.M. Feldmann at site OY3, T. 132 N., R. 75 N., Sec. 1,
Emmons County, North Dakota.
Diagnosis and Description.-- The piece is approximately 2.6
cm tall, .8 cm wide, and .7 cm thick. Fart of the lateral
carina i.s present Figure 16!. The enamel i smooth and
lacks any indication of longitudinal o :azeral division.
Discussior.-- The tooth was identified by Phil Curry of the
Tyrell Museum as a Tyrannosaurid based on he serration on
zhe carina. The piece appears to be fro., near the tip of
the tooth. Unfortunately, the incomp'eze .. ⬠ure of the
tooth preve zs its f..rther identification.
the wears and rears of daily life.
* evel and Age. ⬠⬠This fragment was collected
z Lake/Iron Lightning Member contact in the
.ation. It is Maastrichtian in age.
CLASS Reptilia
SUBCLASS Archosauria
ORDER Saurischia
SUBORDER Theropodia
INFRAORDER Carnosauria
FAMILY Tyrannosauridae
Referred specimen.-- KS Specimen, tooth rragment collected
by R.M. Feldmann at site OY3, T. 132 N., R. 75 N., Sec. 1,
Emmons County, North Dakota.
Diagnosis and Description.-- The piece is approximately 2.6
cm tall, .8 cm wide, and .7 cm thick. Fart of the lateral
carina i.s present Figure 16!. The enamel i smooth and
lacks any indication of longitudinal o :azeral division.
Discussior.-- The tooth was identified by Phil Curry of the
Tyrell Museum as a Tyrannosaurid based on he serration on
zhe carina. The piece appears to be fro., near the tip of
the tooth. Unfortunately, the incomp'eze .. ⬠ure of the
tooth preve zs its f..rther identification.
Page 62
graphic Level and Age.-- This specrmen was recovered
:","=.. «ear the Timber Lake/Iron Lightnrng Member boundry of
."ox Bills Formation. It is Maastrichtian in age.
CLASS Reptilia
Referred Speczmens.-- SLU No. 1832 ⬠fragmentary material,
fragment of metacarpal ?!, and larger, thinner fragment
possibly skull material! collected. from T. 130 N., R. 106
W., Sec. 25, Bowman County, North Dakota.
Diagnosis and Description.-- The larger, thin fragment is
approximately 9.9 cm long, 9.5 cm wide, and ranges in
thickness from 1.1 cm on the left side Figure 18! to a
thin, knife-like edge on the curved and right hand edges
I'igure 18!. The piece is very porous and is perforated by
several nerve canals which intersect the surf~ca of the bone
at approximately 45 degrees. The bone has a curvature which
slightly flattens towards the knife-lake curved edge.
The metacarpal ?! has a maximum hefoht o" 3.3 cm, a
maximum width of 1.6 cm which thine to .55 c.-. and a maximum
depth of 1.5 cm Frgure 17!. The piece has been broken and
only approximately one half of the tot.al none rs present.
The numerous fragments of bone rarge in length from
approximately I cm to approximately 6 cm and range in width
from apprcx':..ately I cm to approximately 6 cm. Most of the
pieces are rectangular in general sha e a..d - e composed of
compac , struts 'r ' bone
:","=.. «ear the Timber Lake/Iron Lightnrng Member boundry of
."ox Bills Formation. It is Maastrichtian in age.
CLASS Reptilia
Referred Speczmens.-- SLU No. 1832 ⬠fragmentary material,
fragment of metacarpal ?!, and larger, thinner fragment
possibly skull material! collected. from T. 130 N., R. 106
W., Sec. 25, Bowman County, North Dakota.
Diagnosis and Description.-- The larger, thin fragment is
approximately 9.9 cm long, 9.5 cm wide, and ranges in
thickness from 1.1 cm on the left side Figure 18! to a
thin, knife-like edge on the curved and right hand edges
I'igure 18!. The piece is very porous and is perforated by
several nerve canals which intersect the surf~ca of the bone
at approximately 45 degrees. The bone has a curvature which
slightly flattens towards the knife-lake curved edge.
The metacarpal ?! has a maximum hefoht o" 3.3 cm, a
maximum width of 1.6 cm which thine to .55 c.-. and a maximum
depth of 1.5 cm Frgure 17!. The piece has been broken and
only approximately one half of the tot.al none rs present.
The numerous fragments of bone rarge in length from
approximately I cm to approximately 6 cm and range in width
from apprcx':..ately I cm to approximately 6 cm. Most of the
pieces are rectangular in general sha e a..d - e composed of
compac , struts 'r ' bone
Page 63
Figure 17.-- Reptilran metacarpal fragment, SLU No. 1S32,
sate ATGSG. Scale bar as 1 cm. A. Sade r ew. B. "Top"
iew ⬠look ..o =" =-=- culatang surface
sate ATGSG. Scale bar as 1 cm. A. Sade r ew. B. "Top"
iew ⬠look ..o =" =-=- culatang surface
Page 64
Figure 18. ⬠⬠Rept'lian Turtle ?!! skull ?! fragment, SLU
No. 1832, site '1050. Scale bar is 1 cr..
No. 1832, site '1050. Scale bar is 1 cr..
Page 65
Due to the extreme fragmentary nature of the
ficat on is extremely difficult. The
pcr-"'-'= bone appears to be skull material and the
may be rib material. The metacarpal
cesar"les '.-. -' seen in Protostega sp.. However,
cation is impossible without a definite
of the thin bone's identity.
Level and Age. ⬠⬠The material was collected-" oi' c
:amber Lake Member of the Fox Hills Formationâ¬
31 feet above the Pierre Shale boundry. It isprcximately
as =.'chi an in Age
CLASS Reptilia
Referred Specimen.-- NDGS specimen, metacarpal collected by
John Hoganson approximately one mile north of s'te A1050.
Diagnosis and Description.-- The metacarpal is 3 cm tall,
has a maximum wrdth of 1.4 cm, and has a maximum thickness
of 1.3 cm Figure 19!. The shaft of the bone 's fairly
smooth and the articulatrng surfaces are rein' ively flat.
D 'scussion. -- This bone is too small to oe identified by
self. Based entirely on conjecture, o e can state that it
.:.ost likely belongs to a mosasaur or turtle.
Szratagraphic Level and Age. -- This bone was collected in
tie 'amber Lake Member of the Fox Hills For=.,ation. It is
Maas richt.=."
ficat on is extremely difficult. The
pcr-"'-'= bone appears to be skull material and the
may be rib material. The metacarpal
cesar"les '.-. -' seen in Protostega sp.. However,
cation is impossible without a definite
of the thin bone's identity.
Level and Age. ⬠⬠The material was collected-" oi' c
:amber Lake Member of the Fox Hills Formationâ¬
31 feet above the Pierre Shale boundry. It isprcximately
as =.'chi an in Age
CLASS Reptilia
Referred Specimen.-- NDGS specimen, metacarpal collected by
John Hoganson approximately one mile north of s'te A1050.
Diagnosis and Description.-- The metacarpal is 3 cm tall,
has a maximum wrdth of 1.4 cm, and has a maximum thickness
of 1.3 cm Figure 19!. The shaft of the bone 's fairly
smooth and the articulatrng surfaces are rein' ively flat.
D 'scussion. -- This bone is too small to oe identified by
self. Based entirely on conjecture, o e can state that it
.:.ost likely belongs to a mosasaur or turtle.
Szratagraphic Level and Age. -- This bone was collected in
tie 'amber Lake Member of the Fox Hills For=.,ation. It is
Maas richt.=."
Page 66
P' gure 9.-- 5 11'a . metacarpal, NDGS pecimen, recovered
approx -... el: mile : om sate A1050. Scale bar is 1 cm.
A. Sr e ; . B. ": p" v ew ⬠lookino o. to articulating
surfac
approx -... el: mile : om sate A1050. Scale bar is 1 cm.
A. Sr e ; . B. ": p" v ew ⬠lookino o. to articulating
surfac
Page 68
60
the deltaic environmental interpretation of the Fox
:-.'lls sediments
the deltaic environmental interpretation of the Fox
:-.'lls sediments
Page 69
REFERENCES
1890. On the characters and Systematic
positron of the large sea lizards, Mosasauridae.e, 16:262 ⬠2
orden L. Jr. and Sheldon, Mary Amy. 1986.
esc zptzon of a very Young Mosasaur from Greens
County, Alabama. Journal of the Alabama Academy of
Science, 57!:76-82.
Bcuchard, T. R. 1990. The Lowez Veztebrates of the Fox
Hills Formation in Meade County, South Dakota. South
Dakota School of Mines and Technology, Rapid City, S.D.
82p.
Bunker, B. J., Witzke, B. J., Watney, W. L., and Ludvigson,
G. A. 1988. Phaneroroic History of tie Cental
Midcontinent, United States, In: Sloss, L. L., ed.
The Geology of North America, Sedimentary Cover ⬠North
American Craton: U.S. The Geological Society of
America, 0-2:243-260.
Sauamata, Mosasauridae! from the Sharon Springs Membez
of the Pzerre Fo nation Campanian of Wyoming [abstrl.
Journal of Vertebrate Paleontology, p. 20A.
Camp, C.L. 1962. Cal fornza Mosasaurs. Be keley:
.vers of Cal fornza Press, 66p
Carper ter, S. :., Er ckson J. M., Lohmann, K. C., and Owen
rageneszs of Fossilzfero s Concretzons
61
1890. On the characters and Systematic
positron of the large sea lizards, Mosasauridae.e, 16:262 ⬠2
orden L. Jr. and Sheldon, Mary Amy. 1986.
esc zptzon of a very Young Mosasaur from Greens
County, Alabama. Journal of the Alabama Academy of
Science, 57!:76-82.
Bcuchard, T. R. 1990. The Lowez Veztebrates of the Fox
Hills Formation in Meade County, South Dakota. South
Dakota School of Mines and Technology, Rapid City, S.D.
82p.
Bunker, B. J., Witzke, B. J., Watney, W. L., and Ludvigson,
G. A. 1988. Phaneroroic History of tie Cental
Midcontinent, United States, In: Sloss, L. L., ed.
The Geology of North America, Sedimentary Cover ⬠North
American Craton: U.S. The Geological Society of
America, 0-2:243-260.
Sauamata, Mosasauridae! from the Sharon Springs Membez
of the Pzerre Fo nation Campanian of Wyoming [abstrl.
Journal of Vertebrate Paleontology, p. 20A.
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Dinosaur Studies; commemorating the 150th anniversary
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Amerrcan Mosasaurs Reptilia, Saurial. New Haven;
Peabody Museum of Natural Hrstory Bulletin 23.
1994. Ui publrshed personal communication.
Sevon, W.D. 1958. A Niobrara Mosasaur of South Dakota.
South Dakota Academy of Science Proceedings,
1957,36:144-146.
Sheldon, M. A. 1993. Ontogenetic Study of Selected
Mosasaurs of North America, Masters Thesrs. University
of Texas at Austin, Austin. 183 p.
Smith, F. G. W. 1956. Monsters of the Ancient Seas. Sea
Frontiers, International Oceanographic Foundation,Mi mi, Fla. pp. 152 ⬠1.
Vaughn, P. P. and Dawson, M. R. 1956. On the Occurrence of
Calcified Tympanic Membranes in the Mosasaur
Piatecarpus. Transactions of the Kansas Academy ot
Science, 59li382-384.
Williston, S.W. 1902. Notes on some new or lrttle known
extinct reptiles. Kansas Universrty Science Bulletin,
I:247-254.
1904. The Relationships and Habrts of the
Mosasaurs. Journal of Geology, 12 l!:43-51.
1914. Water Reptiles of the Fast and
Present. Chrcago: University of Chrcago Press, vi +
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