REPORT 



Of the Committee on Dr. Ruschenberger's Elements of 



Geology. 



The following report upon the Elements of Geology, prepared for 

 the use of schools, &c., by W. S. W. Ruschenberger, M. D. Sur- 

 geon in the U. S. Navy, is respectfully submitted. 



This small volume of 235 pages contains a very accurate and com- 

 prehensive detail of the system now received among learned geolo- 

 gists, and is also illustrated by numerous good drawings of the seve- 

 ral objects most deserving of attention. And it merits public notice 

 for the clear explanations given of the meaning of technical terms, 

 which the learned geologist necessarily employs, but which to the 

 beginner, form a serious difficulty. By these explanations the system 

 is rendered entirely easy to the minds of even very young readers. 



He shows, first, the order of the position of the sea, sedimentary 

 formations and plutonic rocks, the latter being the basis and the 

 other two over it. 



He then states the evidence, that the basis called the first Geolo- 

 gical Epoch — is the result of the power of heat, therefore could not, 

 and does not Qontain any vegetable or animal whatever. 



Then the second Epoch, called transition. This layer or stratum 

 contains the first specimens of animal and vegetable life, few in num- 

 ber and kinds; at this epoch the sea covered the greatest part of our 

 globe; very few vertebrated (back bone) animals are found in it. 



Third Epoch. — This is called the secondary formation, (the trans- 

 ition being the primary,) succeeding it after a long period of quiet 

 repose. In this third period, the strata of sandstone, of congloiu - 



