210 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



and suggests that further observations be prosecuted by the 

 systematic examination of both snow and rain at different 

 seasons of the year in different parts of the globe. 6 ^, Au- 

 gt(st IS, 187 3, 463. 



LESQUEEEUX OX THE FOSSIL PLANTS OF THE NORTHEEN 



HEMISPHEEE. 



An important component of Professor Hay den's report 

 upon the geology of various parts of the West consists of 

 memoirs on the fossil plants, by Professor Leo Lesquereux, 

 well known as among the most accomplished and thorough 

 specialists in that branch of paleontology. The following are 

 among the conclusions arrived at by him, and indicate among 

 other points that the flora of the tertiary period of Europe 

 stands in close relationship to that of America, and is proba- 

 bly derivable from it ; and that, while in Europe and Arctic 

 America it has been materially changed, many of the original 

 features are retained at the present time in the temperate 

 portions of the North American continent. The summary of 

 his views is as follows : 1. The tertiary flora of North Ameri- 

 ca is by its types intimately related to the cretaceous flora of 

 the same country. 2. All the essential types of our present 

 arborescent flora are already marked in the cretaceous of our 

 continent, and become more distinct and more numerous in 

 the tertiary ; therefore the origin of our actual flora is, like 

 its facies, truly North American. 3. Some types of the North 

 American tertiary and cretaceous flora appear in the same 

 formations of Greenland, Spitzbergen, and Iceland ; the deri- 

 vation of these types is therefore apparently from the arctic 

 regions. 4. The relation of the North American tertiary flora 

 with that of the same formation of Europe is marked only for 

 North American types, but does not exist at all for those 

 which are not represented in the living flora of this continent ; 

 therefore the European tertiary flora partly originated from 

 North American types either directly from our continent, or 

 derived from the arctic regions. 5, The relation of the terti- 

 ary flora of Greenland and Spitzbergen with ours indicates, 

 at the tertiary and cretaceous epochs, land connection of the 

 northern islands with our continent. 6. The species of plants 

 common to the cretaceous and tertiary formation of the arc- 

 tic regions and of our continent indicate in the mean temper- 



