McCarty's Mountain (Eocene of the United States)

Also known as North of Big Hole River; South side of McCarty's Mountain; McCartney Mountain; MV 5813; MV 5908; MV 6201; MV 6202

Where: Madison County, Montana (45.5° N, 112.6° W: paleocoordinates 47.3° N, 103.8° W)

• coordinate stated in text

When: Chadron Formation (White River Group), Chadronian (37.2 - 33.9 Ma)

• "Titanotherium beds, Lower White River formation" - Gilmore 1928.

•Lower White River/Titanotherium beds = Chadron Fm (Hoganson et al., 1998)

Environment/lithology: wet floodplain; fine-grained, quartzose, gray tuff

• McCarty's Mountain Lower Oligocene sediments were deposited on a floodplain,

•The water table must have been very near and in places above the surface providing conditions too moist for large trees, but suitable for shrubs and other low vegetation. Frequent and widespread flooding of the floodplain by sluggish streams took place. The flooding could be the result of rainfall or could be caused by faulting and/or plugging of the watercourses by lava and ash from the widespread volcanic activity in the area as postulated by Pardee (1950), Freeman, Ruppel, and Klepper (1958), and Mann (1954). The lower and upper beds in the measured section were deposited at the basin margin as indicated by the very large boulders of andesite brought into the sediment by swift-flowing small tributary streams. The lack of channels in the middle beds could indicate that the margin of the basin had shifted and the area of deposition was no longer at the edge of the basin. Renewed faulting might explain the re-occurrence of tributary channels in the upper beds. However, the lock of any unconformity within the sequence argues against this interpretation.

• The tuff is composed primarily of partially altered shards of volcanic glass with quartz grains, plagioclase, calcite and iron oxides in a clay matrix. The clay matrix, identified by Mr. T. Mowatt using x-ray diffraction, is montmorilionite. The color of the sedimentary tuff, which is due largely to the clays, varies from light buff to light gray. (Riel 1963)

Size classes: macrofossils, mesofossils

Collected by Earl Douglass

Primary reference: E. Douglass. 1905. The Tertiary of Montana. Memoirs of the Carnegie Museum 2(5):203-221 [J. Alroy/J. Alroy/J. Marcot]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 16990: authorized by John Alroy, entered by John Alroy on 15.05.2002, edited by Jonathan Marcot, Terri Cleary and Evangelos Vlachos

Creative Commons license: CC BY (attribution)

Taxonomic list

• placement of Douglass' "Ictops" species, following Novacek 1976: montanus valid, but not Leptictis sensu stricto intermedius syn. of montanus tenuis syn. of montanus major nomen dubium - listed by Tabrum et al. 1996, reason not stated

"Ischyromys typus" is NOT present, this material is "Titanotheriomys": Wood 1980
Reptilia
 Testudines - Pantestudinidae
Testudo peragrans n. sp.6 Hay 1906 turtle
CM 1101 (holotype), a skull and shell
 Squamata - Anguidae
"Helodermoides tuberculatus" = Helodermoides tuberculatus15, "Glyptosaurus montanus n. sp." = Helodermoides tuberculatus5
"Helodermoides tuberculatus" = Helodermoides tuberculatus15 Douglass 1903 lizard
CM 9975, nearly complete skull and gular region, body osteoderms, vertebrae, and ribs
"Glyptosaurus montanus n. sp." = Helodermoides tuberculatus5 Douglass 1903 lizard
CM 1050 (holotype), nearly complete skull and lower jaws, partial limb and phalangeal bones.
Mammalia
 Rodentia - Eomyidae
Paradjidaumo sp.16 Burke 1934 rodent
said to be new
Paradjidaumo cf. trilophus16 Cope 1873 rodent
 Rodentia - Heliscomyidae
Heliscomys cf. ostranderi16 Korth et al. 1991 rodent
 Rodentia - Ischyromyidae
Ischyromys douglassi n. sp.3 Black 1968 rodent
DUPLICATE REF 1085 or 1086
 Rodentia - Cylindrodontidae
Ardynomys occidentalis n. sp.4 Burke 1936 rodent
Pseudocylindrodon medius n. sp.18 Burke 1938 rodent
Cylindrodon sp.18 Douglass 1902 rodent
 Lagomorpha - Leporidae
Palaeolagus sp. Leidy 1856 rabbit
confirmed by Tabrum et al. 1996
? Megalagus sp.16 Walker 1931 rabbit
said to be new
 Lipotyphla - Geolabididae
Centetodon magnus1 Clark 1936 placental
 Perissodactyla - Brontotheriidae
Brontotheriidae indet. Marsh 1873 brontothere
"Titanotherium"
 Perissodactyla - Hyracodontidae
Hyracodon priscidens8 Lambe 1905 odd-toed ungulate
Triplopides rieli n. sp.11 Radinsky 1967 odd-toed ungulate
 Perissodactyla - Rhinocerotidae
Rhinocerotidae indet.16 Gray 1821 rhinoceros
Penetrigonias dakotensis9 Peterson 1920 rhinoceros
 Perissodactyla - Tapiridae
? Colodon cingulatus10 Douglass 1902 tapir
 Perissodactyla - Equidae
Mesohippus sp. Marsh 1875 anchitheriine horse
confirmed by Tabrum et al. 1996
 Tribosphenida - Proscalopidae
Cryptoryctes kayi12 Reed 1954 placental
omitted by Tabrum et al. 1996, reasons unclear
 Tribosphenida - Apternodontidae
Apternodus baladontus n. sp.2 Asher et al. 2002 placental
 Tribosphenida - Micropternodontidae
Micropternodus sp.16 Matthew 1903 placental
 Carnivora - Miacidae
"Miacis" sp.16 Cope 1872 carnivoran
said to be new
 Carnivora - Amphicyonidae
cf. Daphoenictis sp.16 Hunt 1974 bear-dog
 Carnivora - Canidae
Hesperocyon sp.16 Scott 1890 canid
 Ferae - Epoicotheriidae
Epoicotherium unicum14 Douglass 1905 placental
 Hyaenodonta - Hyaenodontidae
Hyaenodon sp. Laizer and Parieu 1838 eutherian
 Theriiformes - Herpetotheriidae
Herpetotherium valens16 Lambe 1908 marsupial
"Peratherium"
Copedelphys cf. titanelix16 Matthew 1903 marsupial
"Peratherium"
 Artiodactyla - Oromerycidae
Montanatylopus matthewi n. sp.7 Prothero 1986 even-toed ungulate
DUPLICATE REF 2800 or 2815
 Artiodactyla - Merycoidodontidae
Merycoidodontidae indet.16 Thorpe 1923 oreodont
large; probably "M. macrorhinus" of Storer 1978
Oreonetes anceps13 Douglass 1902 oreodont
Bathygenys cf. alpha16 Douglass 1902 oreodont
Limnenetes platyceps13 Douglass 1902 oreodont
 Artiodactyla - Agriochoeridae
"Protoreodon minimus" = Agriochoerus minimus17
"Protoreodon minimus" = Agriochoerus minimus17 Douglass 1902 agriochoerid
 Artiodactyla - Leptomerycidae
Leptomerycidae indet.16 Zittel 1893 ruminant
"Leptomeryx" said to be new
"Leptomeryx" aff. speciosus16 Lambe 1908 ruminant