48 ROZELLE PURNELL HANDY 



resources of large and unexplored regions, was beginning 

 to be appreciated by the United States government. The 

 first geological survey made by state authority was that of 

 North Carolina in 1824 and 1825, and the example was soon 

 followed by more or less thorough surveys of the New Eng- 

 land and middle states, and later of the great Mississippi 

 valley and the Rockies. In 1841, shortly after the appear- 

 ance of another great work, entitled Elements of Geology, 

 Lyell visited America, where he was received with great ac- 

 claim. Thirteen months were spent in the United States, 

 Canada and Nova Scotia, during which time he worked hard 

 as an observer and recorder. The science had meanwhile 

 grown to gigantic proportions since he had issued the final 

 installment of his Principles, in 1833. The subordinate 

 branches of geology were being studied with enthusiasm, 

 and the importance of paleontology for chronological pur- 

 poses had become recognized. It was now possible for the 

 geologist to trace the changes which the earth's crust had 

 undergone, and to describe in minute detail the character 

 of the plant and animal life peculiar to each of the great 

 epochs into which time had been divided. 



The solving of the mystery of the coal formation was 

 attended by the most marvelous revelations. The fos- 

 siliferous strata of the subcarboniferous age bore mute 

 testimony that the greater part of North America, Europe, 

 and Great Britain had been submerged to a considerable 

 depth under the sea, immediately preceding the coal bear- 

 ing period. Then there were gentle oscillations, and in 

 time the continents had uplifted themselves to the water's 

 surface, and in this condition they had remained for a very 

 great period of time. The interior of the North American 

 continent from eastern Pennsylvania to central Kansas 

 was one vast jungle of luxuriant vegetation. The Green 

 mountains separated the New England and the Nova Scotia 

 areas from the marshes of Pennsylvania, and the Michi- 

 gan coal area was an isolated marsh region. The plants 

 and trees that flourished in these great marshes during the 

 progress of the carboniferous age were of a luxuriance that 

 has never been approached in any later period. The fossil 



