no 



TITANOTHERES OF ANCIENT WTOMING, DAKOTA, AND NEBRASKA 



GEOGRAPHIC DISTRIBUTION OF THE CHADRON FORMATION 



The following list of localities at which remains of 

 titanotheres have been collected includes some 

 isolated spots where the Chadron formation is rec- 



ognized by a few bones or a single skull, as well as 

 points in the classic areas of the Great Plains where 

 the history of the titanotheres is chiefly recorded. 



Localities at wMcli tlie principal types and collections of Oligocene titanotheres Jiave heen obtained 



South Dakota 



Eegion 



' Mauvaises Terres of Nebraska," 

 Big Badlands of Chej'enne and 

 White Rivers of South Dakota. 

 This region, the one most exten- 

 sively explored, commonly known 

 as the Big Badlands, lies between 

 White and Cheyenne Rivers, 

 southwestern South Dakota, ex- 

 tending over the border into Ne- 

 braska and Wyoming, including 

 the basin of Hat Creek. The 

 lower Oligocene has been well dif- 

 ferentiated in this region, and the 

 records are generally definite. 



Explorations 



Successively explored by mem- 

 bers of the American Fur Co. 

 (1845), John Evans (1853), 

 Meek and Hayden (1853), and 

 by more recent explorers: 

 Hatcher (for the U. S. Geologi- 

 cal Survey, U. S. National 

 Museum, and Yale University 

 collections, 1886, 1887, 1888, 

 1902), Garman (for the Muse- 

 um of Comparative Zoology, 

 1885), Wortman (for the 

 American Museum of Natural 

 History, 1892, 1894), Gidley 

 and Thomson (for the Amer- 

 ican Museum of Natural 

 History, 1902), Thomson (for 

 the American Museum of 

 Natural History, 1904), Dar- 

 ton (for the U. S. Geological 

 Survey, 1905). 



Locality 



Bear Creek _ 



Indian Draw. 



Quinn Draw_ 



Corral Draw 



Type 



Menodus (Titanotherium) proutii 

 (Owen, Norwood, and Evans), 

 Diploclonus (Megacerops) tyleri 

 (Lull), Brontotherium (Tita- 

 nops elatus) gigas Marsh, Men- 

 odus (Menops) varians (Marsh) 

 Brontotherium tichoceras 

 (Scott and Osborn), B. doli- 

 choceras (Scott and Osborn), 

 B. platyceras, B. leidyi Osborn, 

 Brontops validus Marsh, Al- 

 lops crassioornis Marsh, A. 

 serotinus Marsh. 



Brontotherium medium Osborn, 

 B. hatcheri Osborn, Mega- 

 cerops (Symborodon) copei 

 Osborn, Allops (Megacerops) 

 marshi Osborn. 



Diploclonus bicornutus (Osborn) , 

 Brontops brachycephalus Os- 

 born, Brontotherium (Titano- 

 therium) ramosum Osborn. 



Allops walcotti Osborn. 



Nebraska 



White River, northern Nebraska 



Hat Creek, Sioux County, Nebr. 

 Hat Creek, a branch of the South 

 Fork of Cheyenne River, rises in 

 the canyon in the north front of 

 Pine Ridge, Sioux County, and re- 

 ceives numerous branches, also 

 heading in this front. 



Big Cottonwood Creek, Sioux Coun- 

 ty, Nebr. The exposures of the 

 Titanotherium zone at the head of 

 Big Cottonwood Creek are coex- 

 tensive with those of the Hat 

 Creek basin, which lies north of 

 this locality. Much of Hatcher's 

 collecting was done in exposures 

 on the low divide connecting Big 

 Cottonwood Creek with the ex- 

 posures in the Hat Creek basin. 

 Adelia is a station on the Chicago, 

 Burlington & Quincy R. R., on 

 the outskirts of this particular 

 region. 



Marsh and Clifford (for Yale 

 University, 1874). 



Hatcher (for the U. S. Geologi- 

 cal Survey, 1886; for the Car- 

 negie Museum, 1900), Peter- 

 son(forthe Carnegie Museum, 

 1901, 1902). 



Hatcher (for the U. S. Geo- 

 logical Survey, 1886; for the 

 Carnegie Museum, 1900). 



Dry Creek_ 

 Hat Creek. 



Brontops rdbustus Marsh. 

 Brontops dispar Marsh. 



