EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



911 



Mountains, some of the skulls include jaws, but few 

 are found associated with parts of the postcranial 

 skeleton. Only one fairly complete skeleton of a 

 titanothere was foimd in the Shara Murun, a specimen 

 that had been in part destroyed by the weather. 

 This skeleton bears the number Am. Mus. 20277. 

 Incomplete limb and foot bones of six other skeletons 

 were also collected. AU the 17 or more specimens of 

 titanotheres collected, except one titanothere skull 

 with jaws (Am. Mus. 20252), were found in one rather 

 small area just north of the Kalgan-Uliassutai trail. 

 This area, which has a radius of about a third of a 

 mile, was a veritable bone bed, and the large collection 

 of remains of titanotheres obtained from it represents 

 only a small part of the fossils actually weathered out, 

 a fact that indicates the extreme abundance of these 

 titanotheres in central Mongolia in upper Eocene 

 time. 



Protitanotherium mongoUense lije zone. — The faunis- 

 tic name "Protitanotherium mongoUense life zone" was 

 given by Osborn to the Shara Murun formation on 

 determining that the species of titanotheres which 

 they contain are considerably more recent in age than 

 those of the Irdin Manha formation. Altogether 

 more than 17 specimens of titanotheres have been 

 found in a single fossiliferous exposure, distributed as 

 follows : 



Protiianolherium andrewsi, the most progressive species, 

 represented by the type and six other specimens, also skeletal 

 material, probably belonging in upper levels. 



Protiianotheriuin mongoUense, represented b}' the type and 

 five other specimens, .also skeletal material. 



Dolichorhinus kaiseni, represented by the type and three 

 other specimens. 



UPPER EOCENE: IRDIU MANHA FORMATION 

 Granger and Berkey (August 7, 1922, p. 5) 



Locality and characteristic features. — About 25 miles 

 south of the Houldjin formation a conspicuous 

 member of Obruchev's Gobi series, called the Irdin 

 Manha formation, immediately overlies the Upper 

 Cretaceous Iren Dabasu formation. It consists of 

 cross-bedded sandstones, limy sand, and pebbly 

 sandstones and comprises a barren upper member 

 (25 + feet thick) and a lower member, the lophiodont- 

 bearing bed (4 feet thick). Originally characterized by 

 (1) small Lophiodonta of at least two species in great 

 abundance [Desmatotherium]; (2) a perissodactyl 

 .[Protitanotherium] about the size of the upper Eocene 

 titanotheres and possibly related to this family; 

 (3) a small artiodactyl [GoMohyus]; (4) a small creo- 

 dont [Hyaenodon]; (5) an abundance of turtles of 

 both the hard-shelled and soft-shelled groups; (6) 

 teleost fishes. 



Granger (notes, 1925) reports as follows: The 

 Irdin Manha bench, which extends north and south, is 

 about 22 miles southeast of Iren Dabasu on the 

 Kalgan-Urga trail and about 143 miles north of 



Kalgan. The fossiliferous outcrop occurs along an 

 escarpment that is several miles long, with a few out- 

 lying buttes. The Kalgan-Urga trail and the telegraph 

 line drop down over this escarpment at or near the 

 center of the fossiliferous area. Other small exposures 

 of the Irdin Manha formation, sparingly fossiliferous. 



2miles 

 Various Titanotheres 



Telmathenum 



ToUrga ~~""~^^°"' 

 Imile West_ 

 Well °f /'zmila 



Imile North 

 -^, Pniitanotherium grangeri 



Wells °^ AAA 



'/2 mile North 

 ^+ 20109 Dolichorhinus olseni 



TxYs'titanofheremi-Z^CTu ^^ mile South 



yotv 19179 (ref.) V|5Ay//2oio3(type) To Kalgan 



Protitanotherium granger/' 



++?^i06 1 mile South 



Telmatherium berkeyi 



Andrews's owb//poi/iooih 



Eudinoceras mongoliensis 



Figure 771. — Field sketch map of exposures of the Irdin 

 Manha formation 22 miles southeast of Iren Dabasu, on the 

 Kalgan-Urga telegraph line, showing the chief locations at 

 which collections of titanotheres were made 



The points at which fossils were collected extend from 2 miles north to 2 miles 

 south of the telegraph line. The fossils collected are ProtitaTWtherium grangeri, 

 Telmatherium ierkeyi, and DoUchorhinui olseni: also the giant creodont Apdrews- 

 archus and the first giant amblypod found in Asia, Eudinoceras. After sketch 

 by Walter Granger, chief paleontologist of the third Asiatic expedition. 



were observed 20 miles west and 20 miles north of the 

 type locality. 



Fauna. — The lophiodont of the Irdin Manha beds 

 was named by Osborn (October 17, 1923, p. 2) Desma- 

 totherium mongoUense, an animal specifically, if not 

 genericaUy, distinguishable from Desmatotherium 



