400 APPENDIX. 



country of plains, in wliich are occasionally to be seen alluvial 

 hills of moderate elevation ; but the most striking inequalities of 

 surface proceed from the streams which have worn their deep- 

 seated channels through it; and an oceanic overflow capable of 

 covering the country, and producing these strata by deposition, 

 would also submerge all the immense tracts of secondary and 

 alluvial country between the Alleghany and the Rocky Mountains, 

 converting into an arm of the sea the great valley of the Missis- 

 sippi, from the Gulf of Mexico north to the Canadian Lakes. We 

 find in the alluvial soil along the Illinois and Des Plaines blocks 

 of granite, hornblende, and gneiss, of the drift stratum, exhibiting 

 the same appearances of attrition, and of having been transported 

 from their parent beds, which characterize the secondary table- 

 lands along the margin of the great American lakes, the prairies 

 of Illinois, and the western parts of New York. 



There is nothing, perhaps, in the progress of modern science, 

 which has tended to facilitate geological research so much as the 

 study and investigation of fossil organic remains. The}'' teach, 

 with unerring lights, how extensively the ancient flora and fauna 

 of this continent have been prostrated, leaving their exact impres- 

 sions, in all their minuteness, in the newly-formed stratifications. 

 That these impressions, fresh and vivid as we find them, should 

 mark the eras of depositions and crystallization of rocks from 

 the suspension of their elements in water, is the observation of 

 Werner, and it is to him we owe the elements of the Neptunian 

 hypothesis. His general recognition of the epochs of the primi- 

 tive, transition, and secondary rocks, appears too probable not to 

 commend itself to adoption with regard to all strata which can be 

 conceived to be the products of watery menstrua. 



But it remained for Werner, who was the first to perceive an 

 order in strata, also to point out the important application of fossil 

 organic bodies in elucidating their eras, and the natural order of 

 their superposition. 



To adopt the words of Dr. Thomas Cooper : — 



"There appears to be a series of strata, or, as Werner calls 

 them, formations, that may be considered as surrounding the 

 nucleus of the earth. The first formed, or lowest series, always 

 preserve the same situation to each other, except where occasional 

 eruptions, or circumstances not of a general nature, make a variety 



