ENVIRONMENT OP THE TITANOTHEBES 



107 



75 



100 



over many years of arduous exploration for remains 

 of titanotheres: 



The distribution, state of preservation, nature, and character 

 of the animal and plant remains found in the clays and sand- 

 stones, as well as the distribution of the latter, absolutely pre- 

 clude the possibility of their having been deposited in a vast 

 lake and favor the presence of streams meandering through 

 low, broad, level, open or wooded valleys subjected in part at 

 least to frequent inundations, con- 

 ditions very similar to those at 

 present prevailing in the interior of 

 South America, about the head- 

 waters of the Orinoco, the Amazon, 

 and the Paraguay and Parana 

 Rivers. 



Now it is evident that if such 

 conditions prevailed in this region 

 during the deposition of the White 

 River beds there should remain cer- 

 tain evidences concerning it, such 

 as flUed-in river channels and small 

 lagoons with their characteristic 

 deposits and remains of the animal 

 and vegetable life peculiar to each. 

 Moreover, some indication at least 

 of the forests should remain and be 

 found somewhere in this vast region. 

 With these and many other points 

 constantly in mind the writer passed 

 a considerable portion of the seasons 

 of 1900 and 1901 in exploring these 

 deposits. Particular attention was 

 given to ascertaining whether or not 

 they contained an aquatic fauna 

 and flora. The sandstone lenses 

 were especially examined with ref- 

 erence to this, for whether the de- 

 posits as a whole were of lacustrine 

 origin or not, there could be little 

 doubt as to the aqueous origin of the 

 sandstones. Though for the most 

 part remarkably barren of acjuatic 

 life, remains of Trionyx, fishes, and 

 crocodiles were found, and in one 

 locality the casts of unios were ob- 

 served in great numbers. A search 

 in the clays of the Titanotherium 

 and overlying Oreodon beds was re- 

 warded with greater success, for 

 numerous thin layers of limestone, 

 varying in thickness from a fraction 

 of an inch to a foot or more and 

 always of limited areal extent, were 

 discovered at many horizons rich 

 in the remains of fresh-water plants 

 and MoUusca, such characteristi- 

 cally shallow-water forms as Chara, 

 Ldmnaea, Physa, and Planorbis 

 occurring in the greatest abundance. 



plants and MoUusca as are Chara and P/ji/sa at various horizons 

 throughout the White River series, and in the very midst of the 

 region which was supposed to have been occupied by a great 

 lake, and intercalated with the clays which advocates of the 

 the lake theory maintain were deposited in the deep and quiet 

 waters, would appear to preclude the possibility of the existence 

 of such a lake in White River times. Moreover, remains of 

 forests were found at several places and at different horizons 



O 



''Leptcaicheniev 



y^-^^^^--^-^ zone 



.^rr-f^ Promerycochoerus 

 zone 



~^^s^^^^^ zo7ie\ 



pN CHANN EL 5A NDSTONESh 



^: =--^^^=^^ Oreo doTh 

 ^^^^^^ f^^ zorieX 

 j^~^-^2r-^^-^^ = (upper) _\ 



r^AL TERN A tTnG RED A NiTgRA Y LA yEPS 



^^^^^^^^^^Tttcuxotherizurv 



~Z One^r^'DDL E BEDS 



Miohippus 



Mefamynodon 

 Meso/iippus bairdi 



Brontops robusfus 



Brontops d/'spar 



Brontops brachycephalus 



Figure 74. — Section of the Big Badlands of South Dakota showing the chief faunal zones 

 of the Oligocene (White River group. No. 11, fig. 35) and the Miocene 



The Chadron formation ( Tilanotheriiim zone) is shown as determined by the surveys of Hatcher; the divisions of the 

 Brule formation (.Oreodon and Leptauchenia zones) were first established by Wortraan's observations; above is the 

 Arikaree formation of Darton (PromeTycochoerus zone). 



I have submitted these 

 MoUusca to Drs. Dall, Pilsbry, and Stanton, and all have 

 assured me that they belong to species inhabiting swamps 

 and small ponds and could not have lived in the midst of a 

 great lake; while Dr. Knowlton, who has examined the 

 plants, finds in great abundance the stems and seeds of 

 Chara, which, as aU know, is distinctly an inhabitant of small 

 springs, shallow ponds, and brooks. The presence of these 

 thin limestone layers with such characteristically swamp 



throughout these beds. At various localities in the Hat Creek 

 basin in Sioux County, Nebr., I discovered remains of the 

 silicified trunks of trees and seeds belonging especially to 

 Hicoria and Celtis. These were found at various horizons from 

 the middle Titanotherium beds to the very top of the Loup 

 Fork. And in South Dakota, some 12 mUes north of White 

 River, opposite the mouth of Corn Creek, I discovered the 

 remains of a not inconsiderable forest. Here in the upper 

 Titanotherium beds and lower Oreodon beds there occur, actu- 



