278 ANNUAL REPORT SMITHSONIAN INSTITUTION, 11)23 



Morrison fauna, nearly similar in its adaptive facies, and approxi- 

 mately of the same age, but inhabiting a different continent, and of 

 the highest importance in giving some really adequate data as to 

 the faunal distribution at that epoch. It is too early yet to draw 

 conclusions, but my impression from a superficial review was that 

 the Tendaguru and Morrison faunas showed a very close adaptive 

 similarity, but were not so closely related as they seemed. It is, 

 fortunately, possible to correlate the Tendaguru dinosaurs exactly 

 through marine faunas in interdigitating formations. This in turn 

 aids greatly in the correlation of the Morrison fauna, and Schuchert 

 has shown 16 that there is strong reason to place it rather at the 

 end of the Jurassic than at the beginning of the Cretaceous. This 

 conclusion is further supported by Gilmore's new evidence as to the 

 relations of the Potomac fauna. 



CRETACEOUS DINOSAURS OF ALBERTA, MONTANA, AND NEW 



MEXICO 



It is in the Cretaceous dinosaurs that we can record the greatest 

 progress in the last 10 or 15 years. It is not so long ago that our 

 practical knowledge of Cretaceous dinosaurian faunas was almost 

 confined to one horizon and to one small area. Substantially, it was 

 the Lance fauna that we knew, and to what extent the fragmentary 

 fossils recorded from other formations and other areas were really 

 distinguishable from those of the Lance was a subject of acrimonious 

 debate. To-day we have extended the scope of our geographic 

 knowledge as far as central Alberta to the north and New Mexico 

 to the south, and have been able to distinguish four well separated 

 geologic zones, each represented by a fauna known from a series 

 of more or less complete skeletons. The earliest of these faunal 

 zones is the St. Mary's of the Milk River district in Montana; the 

 second and best known is the Belly River of the Red Deer River 

 in Alberta; the third is the Edmonton of the same region, and the 

 fourth, the Lance of Wyoming and Montana. The great collections 

 secured from the Belly River by the American Museum, the Ottawa, 

 Toronto, and Edmonton museums in Canada, and the Field Museum 

 in Chicago are still being prepared and studied, but it is already 

 evident that it was a surprisingly large and varied fauna, of which 

 the Lance was but a remnant, consisting of a few highly specialized 

 survivors. 17 



>«C. Schuchert (1918) : Bull. Geol. Soc. Am., vol. 29, pp. 245-280. 



1T B. Brown (1912-1917) : A series of papers In Bull. Amer. Mus. Nat. Hist. 



H. F. Osborn (1917) : Bull. Amer. Mus. Nat Hist., vol. xxxv, pp. 733-771. 



L. Lambe (1914-1920) : Numerous articles in Mem. Geol. Surv. Canada, Ottawa 

 Naturalist, Trans. Roy. Soc. Canada, etc. 



W. A. Parks (1919-1922) : Series of articles in Univ. Toronto Studies, Trans. Rot. 

 Soc. Canada, etc. 



