94 



TITANOTHEEES OF ANCIENT WYOMING, DAKOTA, AND NEBEASKA 



The researches of Peterson, Douglass, Riggs, and 

 Osborn prove that Washakie B and Uinta B comprise 

 two distinct faunal divisions — a lower, Uinta B 1 

 {MetarTiinus fluviatilis, M. earlei zone), probably cor- 

 responding with the lower levels (B 1) of Washakie B, 

 and an upper, Uinta B 2 {Eohasileus-DolichorJiinus 

 (cornutus) Tiyognathus zone), probably corresponding 

 with the upper levels (B 2) of Washakie B. 



UINTA B 1 (METARHINUS ZONE = ZONE 13) 



Riparian fauna. — The fauna of the MetarTiinus zone 

 was evidently that of a riparian lowland and was in 

 part fluviatile or aquatic, as is indicated by its adapta- 

 tions to aquatic and lowland life, which are inde- 

 pendently developed in members of several different 

 families. These adaptations are indicated by some of 

 the specific names, such as MetarTiinus riparius, M. 

 fluviatilis, two diminutive titanotheres, and DolicTio- 

 rTiinus fluminalis. The animal last named is a short- 

 limbed swamp-dwelling form, a fit companion of the 

 river-seeking rhinoceros Amynodon intermedius , which 

 begins to show aquatic adaptations in the structure of 

 the orbit. The generic aspect of this fauna is almost 

 identical with that of Washakie B, with the single 

 exception that near the summit of Uinta B the ente- 

 lodont ProtelotTierium replaces AcTiaenodon of Washa- 

 kie B. The fauna contains a single new titanothere, 

 RTiadinorTiinus , which is closely related to MetarTiinus. 

 Some of the specific forms are identical with those of 

 Washakie B and some exhibit more recent phases of 

 evolution, which may be represented in the unfossilif- 

 erous upper levels of Washakie B. We consequently 

 reach the broad generalization that Washakie B 1 and 

 Uinta B 1 were not only contemporaneous sediments 

 but that they indicate the prevalence of similar 

 physiographic and climatic conditions at this time on 

 the north and the south sides of the Uinta Range. 



River-cTiannel fauna. — Remains of the small titano- 

 there MetarTiinus have been found in ancient river 

 channels, as determined by Riggs. This genus is by 

 far the most distinctive fossil of this life zone and is 

 apparently confined to it, although at certain levels 

 primitive species of DolicTiorTiinus {D. longiceps) are 

 found in equal abundance (Riggs, 1912.1, p. 20). 

 This life zone, which is 400 feet thick, is composed 

 chiefly of massive ledges of sandstone alternating 

 with layers of sandy shales or indurated clays. In all 

 the ledges there are traces of cross-bedding, and at many 

 places there are beds of coarser river sand containing 

 pebbles of quartzose material, sandstone, and clay 

 shale. In these beds are found disarticulated bones 

 of mammals, as well as the branches and at some 

 places the trunks of trees, all pointing to the action of 

 swiftly flowing streams that swept through a flood 

 plain. Many skulls are found embedded in gravel, 

 with their narial or orbital cavities filled with pebbles 

 such as could be carried only by rapidly flowing water. 

 Another evidence of stream action lies in the dissocia- 



tion of the parts of single skeletons. Whole skeletons 

 have exceptionally been found but little disturbed, 

 lying in a fine-grained homogeneous sandstone, ap- 

 parently deposited in quieter water, such as deep 

 pools or eddies. Remains of the long-headed titano- 

 there DolicTiorTiinus are found only in the heavy sand- 

 stones, so that this animal was apparently confined to 

 the vicinity of streams. Supposed river-frequenting 

 species of MetarTiinus, always found in sandstone, in- 

 clude M. fluviatilis, M. riparius, and M. earlei. The 

 species last named is found also in the lower levels of 

 Washakie B, north of the Uinta Mountains. As we 

 ascend in this MetarTiinus zone we find, according to 

 Riggs (1912, p. 24), increasing numbers of upland 

 forms. The "MetarTiinus sandstone" ledge that caps 

 this zone has yielded the type specimens of Doli- 

 cTiorTiinus superior, MetarTiinus riparius, and M. earlei, 

 the last-recorded appearance of these animals in the 

 Uinta Basin. 



UINTA B 2 (EOBASILEUS-DOLICHORHINUS ZONE = ZONE U) 



In the beds of the Eohasileus-DolicTiorTiinus zone the 

 river sandstones and channel deposits gradually give 

 place to shales and clays, indicating physiographic 

 changes in this part of the Uinta Basin. In the lower 

 100 feet of bluish or grayish shales, which are overlain 

 by 40 feet or more of fine red clays, little evidence of 

 mammal life is found, but certain thin beds contain frag- 

 ments of Eohasileus. As we rise in the formation the 

 gray "clays" begin to yield a mixed fauna of lowland 

 and plains forms, including Protylopus and Stylinodon, 

 together with remains of DolicTiorTiinus (cornutus) 

 TiyognatTius and Amynodon intermedius. The massive 

 "Amynodon sandstone," which forms the summit of 

 this life zone, yields the type specimen of the long- 

 headed titanotheres DolicTiorTiinus (cornutus) Tiyog- 

 natTius, D. fluminalis; also of StJienodectes incisivus. 

 This is the last appearance of the genus DolicTiorTiinus 

 in the Uinta Basin. Doubtless the massive "Amyno- 

 don sandstone" terminated the active period of 

 fluviatile and flood-plain deposition in this locality. 

 The D. (cornutus) TiyognatTius zone yields the large 

 enteledont RrotelotTierium uintense, which is inter- 

 mediate between AcTiaenodon insolens of Washakie B 

 and ElotTierium of the White River group. This 

 sandstone contains also the lophiodont DesmatotTie- 

 rium guyoti, which is a forerunner of Colodon of the 

 White River (Oligocene) group. 



ZONE 15: DIPLACODON-PEOTITANOTHERIUM-EPIHIPPnS ZONE 

 [Uinta C I; Xudian of Europe] 



To zone 15 belong the Uinta of King and Marsh, the 

 "Brown's Park beds" of Powell, and the Uinta(?) of 

 the Beaver Divide, Wind River Basin. This zone 

 (Uinta C 1) is correlated with the European stage 

 that was named Ludian, after the "marnes de Ludes" 

 in the Paris Basin, a stage typified by the "gypse de 

 Montmartre," made famous by the classic researches 



