September i5, 1922] 



SCIENCE 



293 



cross-bedded and well cemented. The middle 

 members become finer grained, more mixed 

 with clay and more variable in color. The 

 upper beds are dominantly clays and sandy 

 clays and very fine sands, varying in color 

 from white to dark red and drab and yellow- 

 ish green. No less than twenty distinct beds 

 or layers can thus be distinguished, all of 

 which are regarded as belonging to a single 

 geologic formation. 



Only the lower members of this "Iren 

 Dabasu" formation have been found to be fos- 

 siliferous. The list includes : 



1. Predentate dinosaurs, probably of the 

 bipedal type. 



2. Carnivorous dinosaurs of at least two gen- 

 era, the smaller one being of the Ornitlwmimus 

 type. 



3. Crocodiles. 



4. Turtles of the Trionyx type. 



5. A few peleeypod shells. 



The geologic column for the Iren Dabasu 

 basin therefore is essentially as in the follow- 

 ing table : 



3. An artiodaetyl of the size of a Virginia deer. 



4. An enormous mammal, probaibly a perisso- 

 daetyl and possibly related to or identical witli 

 Bahichitherium, discovered by Forster Cooper in 

 Baluchistan. 



5. A tortoise of large size. 



There is a sharp physical change immedi- 

 ately below this formation and only the coarse 

 sandy conglomeratic member at the very base 

 has been found to be fossiliferous. The fossil 

 remains are unusually fragmentary. 

 Irdin Manha Formation (Early Tertiary) 



For the early Tertiary beds found twenty- 

 five miles farther south, also assumed properly 

 to belong to Obretcheff's Gobi Series, we pro- 

 pose to use the term "Irdin Manha forma- 

 tion." It appears to lie immediately on Cre- 

 taceous beds, the Iren Dabasu formation, and 

 again there is a sharp change in type of rock. 

 The beds are cross-bedded sandstones, limy 

 sands and pebbly sandstones. Only the lower 

 member has been found to be fossil-bearing. 

 It is characterized bv the following forms : 



The Houldjin Beds (Middle Tertiary) 

 For the late Tertiary beds found five miles 

 farther south and belonging to the Gobi Series 

 of Obreteheff we propose the term "Houldjin 

 Beds," taken from the local name of the up- 

 land formed by these beds. They are charac- 

 terized by the following fossil content: 



1. A rhinocerid. 



2. A laree carnivore. 



(1) Small Lophiodonta of at least two species 

 in great abundance; (2) A perissodactyl about 

 the size of the Upper Eocene titanotheres and 

 possibly related to this family, (3) A small 

 artiodaetyl; (4) A small creodont; (5) An 

 abundance of turtles of both the hard-shelled 

 and soft-shelled -groups; (6) Teleost fishes. 



Henry Fairfield Osborn 

 American Museum op Natural History 



