EOCENE AND OLIGOCENE TITANOTHERES OF MONGOLIA 



903 



In the seasons of 1922 and 1923 the third Asiatic 1 formations are more or less clearly recognizable and 

 expedition discovered 10 Tertiary formations within | correlated with those of Europe, Asia, and North 

 the Gobi series as designated by Obruchev. These | America by the fossils they contain, as follows • 



Tertiary formations of Mongolia, in descending order 



Estimated 



thickness 



in feet 



Geographic region 



Probable or estimated age 



American correlation equivalent 



Hung Kureh_ 

 Pang Kiang.- 

 Loh 



Hsanda GoL. 



Houldjin 



Ardyn Obo.. 



SharaMurun. 



Irdin Manha. 



Arshanto. 

 Gashato- _ 



2,000 



500 



100-1, 000 



3,000 



30 



500 



500 



40-100 



40-100 

 300 



Eastern Altai 



Iren Dabasu Basin. 

 Eastern Altai 



Hipparion,Camelus? zone. 



_do_ 



Iren Dabasu Basin_ 

 Uliassutai trail 



-do. 



Iren Dabasu Basin. 



do 



Eastern Altai. 



Serridentinus (Trilopho- 



don) mongolieusis zone. 



Baluchitherium grangeri 



zone. 

 Baluchitherium grangeri? 

 zone. 

 Brontops gobiensis 

 zone. 



Proti t anotlierium 

 mongoliense zone. 



Protit anotherium 

 grangeri zone. 



Lophiodont-Schloss e r i a 



zone. 

 Palaeostylops iturus zone. 



Upper Pliocene or lower 



Pleistocene. 

 Pliocene?; age very 



doubtful. 

 Lower Miocene 



7,150 



Lower and middle Oli- 



gocene. 

 do 



Lower Oligocene. 

 Last? appearance of 

 titanotheres. 



Summit of Eocene. Ti- 

 tanotheres very abun- 

 dant. 



Upper Eocene. Titano- 

 theres present. 



Middle? Eocene. 



Basal Eocene or Upper 

 Cretaceous. 



Oreodou and Metamy- 

 nodon. 



White River group, 

 Chadron formation. 



Uinta formation (Dipla- 

 codon zone). 



Bridger formation 

 (Eobasileus zone) , 

 horizon B of Uinta 

 Basin. 



Bridger formation (?). 



Possibly Puerco, Torre- 

 jon, or Fort Union 

 formation of the 

 Eocene. 



PIIOCENE OR PLEISTOCENE: HUNG KUEEH 

 FORMATION 



Berkey and Granger (May 25, 1923, p. 9) 



Thickness. — The sub-Altai Hung Ku- 

 reh formation, named after the hills of 

 Hung Kureh, measuring in thickness 

 approximately 2,000 feet, rests conform- 

 ably upon the Hsanda Gol formation 

 and is marked above by Pleistocene 

 erosion. It lies in the very bottom of 

 the basin of Tsagan Nor, between the 

 foot of the mountain of Baga Bogdo 

 and the Tsagan Nor itself, and consists 

 of a series of gravelly sands and con- 

 glomerates of great variety and thick- 

 ness, at the base of which lie whitish 

 and yellowish sands and clayey sands. 

 Although the formation is not so well 

 exposed as the Hsanda Gol, it has been 

 possible to measure more than 1,000 

 feet of it, and a reasonable estimate of 

 its total thickness in the type locality — 

 the hills of Hung Kureh— is 2,000 feet. 

 On its extreme margin next to the moun- 

 tain of Baga Bogdo the upper beds 

 101959— 29— VOL 2 37 



Figure 765. — Map of central Mongolia (Gobi Desert region), traversed by the 

 third Asiatic expedition, Roy Chapman Andrews, leader 



Dotted lines show main routes and location of the chief Cretaceous and Tertiary exposures: Iren Dabasu 

 (Upper Cretaceous) , north of Irdin Manha (Tertiary, upper Eocene), Pang Kiang (Tertiary, Miocene?) 

 Ardyn Obo (Tertiary, lower Oligocene), and Djadochta (IjOwer Cretaceous, Protoceratops zone). This 

 area includes about 475,600 square miles and lies northwest of Kalgan and Peking. After Berkey and 

 IM orris, The great bathylith of central Mongolia, p. 2, fig. 1, 1924. 



