534 Lee — Recent Discovery of Dinosaurs in the Tertiary, 



of Ceratopian remains and a Tertiary mammal in the same for- 

 mation (Dawson). Messrs. J. W. Gidley and C. W. Grilmore 

 have called the writer's attention to a similar occurrence in 

 Patagonia, where, according to these authorities, ''there is a 

 commingling* of dinosaurs with mammals which are apparently 

 of undoubted Tertiary age." But F. B. Loomis,f who has col- 

 lected from some of these beds, doubts the contemporaneity of 

 the dinosaurs and the mammals. However, Sinclair;): says of 

 them " It seems to be positively established that dinosaurs and 

 mammals occur in the Notostylops beds. The mammals are 

 not like those known elsewhere from the Cretaceous but are 

 of highly advanced type comparable to those of the Puerco 

 Paleocene of North America. Either we must admit that 

 dinosaurs existed during the Tertiary in South America or 

 change our ideas regarding Cretaceous mammalian types.'' The 

 recent examination of the structural relations of the Dawson 

 arkose to the underlying beds, as well as the fossil plants and 

 mammal, tends to establish its Tertiary age and to necessitate 

 the acknowledgment that Ceratopsian dinosaurs existed in the 

 Pocky Mountain region in early Tertiary time. 



* Ameghino, Florentino: Les formations sedimentaires du Cretace superieur 

 et du Tertiaire de Patagonie: Museo Nacional de Buenos Aires, Anals, vol. 

 xv, ser. 3, viii, 1906. 



Also, Both, Santiago : Beitrag zur Gliederung der Sedimentablagerungen 

 in Patagonien und der Pampas region, Neues Jahrbuch, Beilage Band xxvi, 

 pp. 92-150. 1908. 



f Personal communication. 



% Sinclair, William J. : Contributions to geologic theory and methods by 

 American workers in vertebrate paleontology, Geol. Soc. America, Bull., 

 vol. 23, No. 2, p. 263, 1912. 



