384 NATURE AN0 CHARACTERS 



that class also, although the order of succession 

 should in any particular instance be deficient or 

 irregular. It has appeared in the course of geo- 

 logical investigations, that the red sandstone was 

 the last rock in the order of succession downwards 

 which thus holds a position unconformable to the 

 primary strata ; and its claims to be considered 

 the lowest or first of the secondary class, have 

 been further confirmed, by finding that it was 

 formed from the fragments of the primary, or of 

 preceding, rocks, and, not unfrequently, even 

 from the ruins of those very strata with which it 

 was in contact, or which occupied the nearest 

 place to it. 



Thus the boundary line between the primary 

 and secondary classes seems to have been properly 

 placed between this substance and the nearest 

 primary rock with which it is in contact., or im- 

 mediately below the red sandstone ; it having 

 been already seen, that the inconstant order of 

 succession in the primary class, must render it 

 impossible to determine what that rock may be. 

 As already shown in the table of succession, every 

 rock, from granite through the whole series of 



