466 STUDIES FOR STUDENTS 



prevailed over North America, Greenland and Europe, reaching: 

 to Spitzbergen. Dall says 1 it may be considered as reasonably 

 certain "that the period during which in the arctic regions the 

 last temperate flora flourished was in a general way the same for 

 all parts of the arctic. It would seem highly improbable that 

 a temperate climate should exist in Spitzbergen and not at the 

 same time in Greenland and Alaska, or vice versa." Moreover 

 the nature of the plants of the regions named forms the basis of 

 this statement. The Kenai beds are regarded as fresh water 

 deposits and represent a low land area, which was subsequently 

 still further depressed allowing the Miocene sea to cover it. 

 Dawson 2 says : 



It would be rash to decide on the climatal conditions on the west coast 

 of America in the Eocene period, from the plants yet known. But so far as- 

 they can give information we may infer that the Cretaceous climate was 

 somewhat warmer than that of the Eocene, but that both attained a higher 

 temperature than that of the present day in the same latitudes, while in the 

 Miocene age the climatal conditions were not very different from those now 

 prevailing in the region. 



The Fort Union beds are perhaps the oldest that have been 

 certainly determined to be Eocene. They occupy the plains 

 region of the north. Their limit to the south is unknown, but 

 Haworth 3 believes that near the beginning of Eocene time 

 Tertiary deposits spread continuously from the Dakota- Nebraska 

 area over western Kansas, Indian Territory, and Texas. 



Immediately succeeding or perhaps in part contemporaneous 

 with the Fort Union deposits a series of so-called lake deposits 

 was formed on the plains of the summit region bordering the 

 Rocky Mountains on the east. Elevation or warping of the 

 continent and especially of the mountains of this region appears 

 to have checked the drainage in certain directions, so as to form 

 lakes. The oldest and lowest of these deposits are toward the 

 south and west (Puerco); the newest and highest toward the 

 north and east. Probably during Eocene time the uplift in this 



Seventeenth Ann. Rep. U. S. Geoi. Surv. 1895-6, Part I, p. 839. 



2 Proc. Roy. Soc. Can., n. s., Vol. I, p. 151, 1895. 



3 The Univ. Geol. Surv. of Kans., Vol. II, p. 253, 1896. 



