STRATIFIED 110CRS* 



183 



the lower igneous rocks, is doubtless to be attributed to their for- 

 mation upon the surface, instead of under pressure. The term 

 hypogene includes the plutonic, and metamorphic rocks. 



The sedimentary rocks are termed fossiliferous, or fossil-bear- 

 ing, in distinction to the igneous, or plutonic rocks, in which, by 

 the action of heat, all fossil remains are wanting. The stratified 

 rocks were originally deposited in a horizontal position as repre- 

 sented in this engraving, but they are rarely seen perfectly hori- 



zontal, hence, it is inferred, that subsequently to their deposition* 

 they have been subjected to a variety of disturbing causes, by 

 which they have been made to assume all inclinations to the 

 horizon. Occasionally they are uplifted to an almost vertical po- 

 sition, as in the following illustration, exhibiting the strata on 

 which Powis Castle is built; when by being thus upheaved, the 



edges of the strata are denuded, or uncovered, they are said to 

 crop out, when this occurs, it will be found that the strata suc- 

 ceed each other in regular order, as we have already mentioned. 

 When strata crop out, it is apparent, that having been elevated by 



