^CHRONOLOGICAL ARRANGEMENT OF STRATA.. 187 



CHAPTER II. 



t 



ChrouQlogical Arrangement of Strata. 



** What once had beejv the solid earth, I saw 

 To be a strait ; and from the waves new lands 

 Arose. Far off from the resounding sea, 

 The shells were strown about." Ovid. 







ALTHOUGH geologists are perfectly agreed as to the order of suc- 

 tfsssion of the various strata, yet they have different methods of 

 expressing the same fact In ether words, the names which are 

 used to designate the different formations vary somewhat, but in 

 the great leading features all are agreed. Thus, it matters little, 

 whether, after having divided all rocks into two great classes, 

 fossiliferous, and non-fessiliferous or meiaraorphic, we subdivide 

 ithe former with Dr. Bucklaad, into alluvium, diluvium, tertiary, 

 and the secondary or transition series; or with Dr. Mantell, into 

 modern and ancient alluvium, tertiary strata, and secondary for- 

 jnations; both include the same classes of rocks; or whether we 

 game a certain order of rocks the saliferous strata, or the upper 

 and lower red sandstone; both mean the same thing. The classi- 

 fication which we have adopted is principally that of Dr. Man- 

 tell, who gives the following as the chronological arrangement of 

 the strata, commencing with the uppermost or newest deposits. 



I. FOSSILIFEROUS STRATA. 



1. MODERN AND ANCIENT ALLUVIUM. Comprising the modern 

 and superficial deposits of waterworn and transported materials, 

 sometimes called drift, and consisting of gravel, boulders, sand, 

 %clay, &c. The modern deposits are characterized by the remains 

 f man, and contemporaneous animals and plants. The ancient, 

 sometimes called Diluvium, by an immense proportion of large 



