900 



EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



from the Jurassic downward, had been described by 

 Von Richthofen and later by Bailey Willis in his 

 "Researches in China" (1907). 



The geologic personnel of the third Asiatic expedi- 

 tion iacluded Charles P. Berkey as chief geologist, 

 Frederick K. Morris as geologist and topographer, 

 and Walter Granger as vertebrate paleontologist. 

 The party under Andrews consisted of 25 persons — 

 S Americans, 8 Chinese, and 9 RIongohans. 



A single mammalian tooth found by Obruchev in 

 the Iren Dabasu Basm (Houldjin? formation) was 

 identified by the Vienna jSIuseum as a rhiuocerid ; it is 

 probably BalucMiherium, which occurs in the Houldjin 



ORDERS OF MAMMALS REPRESENTED IN THE COIIECTIONS 



The entire Mongolian collections from the 10 

 Tertiary formations are more or less clearly recognized 

 as belonging to the following orders of mammals: 



Inseotivora of the primitive familj' Pantolestidae. 



Creodonta, archaic small-brained carnivores, fairly numerous. 

 Hyaenodontidae, Oxyaenidae, Mesonychidae. 



Carnivora, modernized large-brained carnivores, less numerous,, 

 first appearing in the upper Eocene (Miacidae) and lower 

 and middle Oligocene (Canidae, Viverridae). 



Rodentia, modernized types of rodents, extremely numerous in 

 the middle Oligocene. 



Amblypoda, archaic small-brained ungulates, very rare, dis- 

 appearing in the upper Eocene. 



Figure 761.^World chart of 1900 explaining Osborn's theory of the central Asiatic origin of the tliirteen orders of holarctic 



mammals, which spread westward to Europe and eastward to North America 



After Osborn, 1900.182, p. 567, Chart IV. 



gravel. The fossils collected by the third Asiatic 

 expedition (1922-23) from the formations of upper 

 Eocene and of lower and middle Oligocene age, the 

 Mongolian formations best known as yet, so far as 

 catalogued, include 406 specimens, distributed among 

 zones and formations as follows: 

 Baluchitherium grangeri life zone: 



Hsanda Gol formation, upper part (middle Oligocene). 150 

 Houldjin formation, upper(?) part (middle Oligocene). 8 

 Brontops gohiensis life zone: 



Ardyn Obo (lower OUgocene) 46 



Protitanotherium mongoliewte life zone : 



Shara Murun (uppermost Eocene) 77 



Protitanotherium grangeri life zone: 



Irdin Manha (upper Eocene) 99 



Arshanto (middle? Eocene) 6 



Gashato (basal Eocene or upper Cretaceous) 20 



Artiodactyla, modernized even-toed ungulates, small and rare- 

 in the older formations. Tragulina, Helohyidae, Anthraco- 

 theriidae. 



Ancylopoda, highly specialized clawed ungulates, ver}' rare. 

 Schizotherium in the Ardyn Obo. 



Perissodact3da, modernized odd-toed ungulates, very numerous,, 

 representing families of Lophiodontidae, of Amj'nodontidae, 

 of Baluchitheriinae, of Hyracodontidae, and of Bronto- 

 theriidae. 



Proboscidea, lower Miocene trilophodonts, lower Pleistocene- 

 elephants. 



FAMILIES ABSENT 



Conspicuous by their absence in these Eocene and 

 Oligocene formations of Mongolia are the primitive 

 three-toed horses of the perissodactyl family of the 

 Equidae. The role of these small, swift, cursorial 

 quadrupeds seems to have been taken in upper 



