446 STUDIES FOR STUDENTS 



and sand with round ferruginous concretions and numerous beds,, 

 seams, and local deposits of lignite ; great numbers of dicoty- 

 ledonous leaves, stems, etc." Under the name Paskapoo, Tyrrell 

 describes this formation as being at least 5700 feet in thickness 1 1 

 "The beds consist of more or less hard, light gray or yellowish- 

 brownish weathering sandstone, usually thick-bedded, but often 

 showing false bedding; also of light bluish-gray and olive sandy 

 shales, often interstratified with bands of hard lamellar ferrugi- 

 nous sandstone, and sometimes with bands of concretionary blue 

 limestone, which burns into an excellent lime. The sandstones 

 consist of very irregular, though slightly rounded, grains of 

 quartz, felspar, and mica, cemented together in a calcareo-argil- 

 laceous matrix." 2 Its fauna shows that this entire series is of 

 fresh-water origin. 



Because of the nature of the stratigraphy of the rocks of 

 this region, and because of the fact that dinosaurs became 

 extinct immediately before the Paskapoo epoch, because a time 

 of great disturbance "in which the Rocky Mountains were 

 uplifted" preceded the Paskapoo, Tyrrell thinks this break 

 between the Cretaceous and Paskapoo marks the close of 

 the Cretaceous, "and that the Tertiary epoch began with the 

 commencement of the Paskapoo period, during which a great 

 thickness of sandstones and sandy shales was laid down without 

 any apparent break or unconformity. In this Paskapoo series,, 

 then, we have the representative of the Eocene of Europe." 3 



Weed, writing of the Crazy Mountains of Montana, says 4 :. 

 "These mountains are formed of Livingston beds, conformably 

 overlain by a series of sandstones and clay shales, characterized 

 by fresh-water fauna, and lithologically distinct and readily dif- 

 ferentiated from the somber-colored sandstones of volcanic 

 material composing the Livingston beds. The plant remains of 

 these [upper] beds are not of Laramie nor of Denver bed types, 

 but are species characteristic of the strata in the vicinity of Fort 



'Geol. and Nat. Hist. Surv. of Canada, Ann. Rep. n. s., Vol. II, p. 135 E. 1886. 



2 Tyrrell : loc. cit., p. 136. sLoc. cit., p. 138. 



" Amer. Geol., Vol. XVIII, pp. 204, 205, 1896. 



