202 The Vilest American Scientist. 



The fossil plants of the Pliocene of Nevada County, Cal. , indi- 

 cate a climate analagous to that of the Southern Atlantic States of 

 the present. 



The fossil palms which are found in abundance in the lower 

 lignitic measures of this continent, especially in Colorado, and even 

 so far north as Vancouver's Island seem to indicate a gradual 

 dimunition of atmospheric heat, from the Eocene to the Glacial 

 Epoch. 



The two species of Sequoia of California are rare and venerable 

 remnants of the flora of the Tertiary, passed through untold cen- 

 turies, giving us a glimpse of the living representatives of the 

 giants of former periods. 



Many of the characters which would be of interest to the reader 

 of the book have doubtless been obliterated, and others so mixed 

 and scattered that, in the present state of our knowledge, they 

 correspond to the "pi" of the printer, and require the skill of 

 trained and advanced scientists to arrange them in the order of 

 their continuity. 



Prof Leo Lesquereux says, ' For the determination of the 

 epochs, if we may call epochs arbitrary divisions of time estab- 

 lished for convenience by geologists, we have to consider the doc- 

 uments relating to their history, and those are mostly the fossil 

 remains of their floras.' 



During the Tertiary period, large portions of this continent 

 were covered with swamps and heat-bogs which served as reser- 

 voirs for the deposit of the vegetable remains which form the 

 lignites and coal. 



According to Dr. J. G. Cooper, who has made a special study 

 of the coal-bearing rocks of the Pacific Coast, the fossil shells 

 found in connection with the coal, show that it was formed by 

 accumulations of trees, etc., in shallow bays, at the mouths of 

 rivers, in fresh or brackish water, and therefore along the shores 

 of older continents or large islands. 



The true coal of the carboniferous recks in other countries was 

 formed from the tree ferns, Algae and othei' plants of low organ- 

 ization. The coal of our coast contains remains of coniferous and 

 dicotyledonous trees, and has hence been considered of more 

 recent age, namely, cretaceous and Tertiary. 



The coal-beds of Mount Diablo, Cal., Bellingham and Coos 

 Bays, and Vancouver's Island are of cretaceous or Eocene age, 

 while the lign.te beds of lone Valley and of Lincoln, Calilornia, 

 according to the testimony of the fossil plants found in them, are 

 probably of Pliocene age. 



Dr. Hayden has estimated that the Great Lignitic or Western 

 Coal Regions cover an area of, at least, 100,000 square miles. 



At the close of the Pliocene Epoch, evidences are found of great 

 changes in the topography of this region by volcanic action, which 

 destroyed the then existing tropical fauna and flora. 



