cretaceous dinosaurs 407 



Cretaceous Dinosaurs of Alberta, Montana, and ISTew Mexico 



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

 ress in the last ten or fifteen years. It is not so long ago that our prac- 

 tical 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. Today we have ex- 

 tended 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 distin- 

 guish 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 Saint Mary's of the Milk Eiver district in Mon- 

 tana ; 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 Ed- 

 monton museums in Canada, and the Field Museum in Chicago are still 

 being prepared and studied, but it is already evident that it was a sur- 

 j^risingiy large and varied fauna, of which the Lance was but a remnant, 

 consisting of a few highly specialized survivors.^^ 



Another interesting phase of recent progress in this group is the prob- 

 able difference in faunas widely apart geographically and in different 

 climatic zones. The splendid specimens secured by Charles H. Sternberg 

 in the last two seasons in the San Juan basin of ISTew Mexico appear to 

 represent a fauna widely different from any of the three great northern 

 faunas. Their true correlation has yet to be determined by a more exact 

 study of the fauna and stratigraphy, but Mr. Sternberg's latest work, 

 performed under heavy handicaps, opens up an important new field for 

 dinosaur collecting and is the last of a long series of important finds made 

 by him during the last fifty years. A fine skull and much of the skeleton 

 of a gigantic Ceratopsian has been secured by the American Museum; 

 other important specimens are still in his hands and in the Upsala Mu- 

 seum in Sweden. 



!<' B. Brown: (1912-1917.) A series of papers in Bull. Am. Mus. Nat. Hist. 



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



L. Lambe : (1914-1920.) Numerous articles in Mem. Geol. Sur. Canada, Otta^Ya 

 Naturalist, Trans. Ro3^ Soc. Canada, etc. 



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

 Soc. Canada, etc. 



