ENVIEONMENT OF THE TITANOTHEKES 



111 



Localities at which the principal types and collections of Oligocene titanotheres have been obtained — Continued 



Colorado 



Region 



Explorations 



Locality 



Type 



Northeastern Colorado, Logan and 

 Weld Counties, exposures south 

 of the Pawnee Buttes escarpment 

 and some distance north of the 

 South Platte River. The lower 

 Oligocene was differentiated and 

 explored by Cope in 1873, but it 

 has hardly been touched by any 

 subsequent work (Horsetail Creek 

 beds of Matthew). 



Lower Oligocene has been recognized 

 at other points in Colorado, as in 

 the vicinity of Akron, but no 

 adequate collections have been 

 made for the identification of 

 species. 



Castle Rock conglomerate (upper 

 part of " Monument Creek beds"), 

 Colorado. 



Marsh (for the Yale Museum, 

 1870), also field collectors. 



Cope 1873, Matthew, Brown, 

 Martin (for the American 

 Museum of Natural History, 

 1898), Matthew, Brown (for 

 the American Museum of 

 Natural History, 1901). 



Darton (for the U. S. Geological 

 Survey, 1905, 1906). Richard- 

 son (for the U. S. Geological 

 Survey, 1912). 



Probably in Weld 

 County, Colo.; 

 near Gerry's ranch, 

 Colo.; also 4 

 miles south of 

 Pond Springs, 

 Colo. Collector, 

 Devendorf. 



Horsetail Creek , 

 Colo. 



Brontotherium gigas Marsh, 

 M e n o d u s (Brontotherium) 

 ingens Marsh, Brontotherium 

 (Titanops) curtum Marsh. 



Megacerops (Symborodon) acer 

 Cope, M. (S.) altirostris Cope, 

 M. (S.) bucco Cope, M. (S.) tor- 

 vus Cope, Menodus (Symboro- 

 don) trigonoceras Cope, M. (S.) 

 heloceras Cope, M. (S.) hypo- 

 ceras Cope, Megacerops riggsi 

 Osborn. 



Wyoming 



Beaver Divide, Fremont County, 

 Wyo. 



Bates Hole, Natrona County, Wyo. 

 Exposures lying between Bates 

 Hole, at the north end of the 

 Laramie Plains, and Beaver 

 Divide, at some distance to the 

 west, have been casually examined 

 by W. H. Reed and W. D. Mat- 

 thew, who have recognized a 

 lower Oligocene fauna, but no 

 S3'stematic exploration has been 

 made. A number of well pre- 

 served specimens of titanotheres 

 (Univ. Wyoming Mus.) were 

 found in this area. 



Granger (for the American Mu- 

 seum of Natural History, 

 1910). 



Reed (for the University of 

 Wyoming, 1907, 1908). 



Pipestone Creek and Thompson 

 Creek, Jefferson County, Mont. 

 In southwestern Montana, at 

 Pipestone Springs, McCarty 

 Mountain, north of Dillon, and 

 elsewhere, small scattered expo- 

 sures. A considerable fauna, of 

 small species, has been described 

 from these beds. 



Douglass (for the Carnegie Mu- 

 seum, 1899, 1901, 1903), 

 Matthew (for the American 

 Museum of Natural History, 

 1902). 



Saskatchewan 



