37.9 



PRELIMINARY REMARKS ON THE NATURE AND 

 CHARACTERS OF THE SECONDARY CLASS. 



IN examining the characteristics of the pri- 

 mary class, many of the remarks applicable to 

 the present, were unavoidably anticipated. It 

 was there shown, that it has received this name 

 because the rocks included in it are esteemed of 

 posterior date to those ranked in the primary 

 division. That fact is deduced from multiplied 

 observations, which prove that where the stra- 

 tified members of both classes occur in the same 

 place, the one is invariably superior to the other ; 

 and that, as no such member of the primary class 

 is ever found intruding among the secondary 

 strata, so no secondary stratum is ever found 

 included between two strata of the primary 

 class. 



But in the secondary class there is also com- 

 prehended a great variety of unstratified rocks ; 

 analogous to granite, as well in their leading 



