OF CREATION. 103 



CHAPTER VI. 



THE CLOSE OF THE FIRST EPOCH OF CREATION. THE MAGNESIAN 

 LIMESTONE, OR PERMIAN SYSTEM OF DEPOSITS. 



AFTER the coal-measures had been deposited in 

 the creeks and at the mouths of rivers, and probably 

 very near the land anciently existing, a great change 

 seems to have taken place in the northern hemis- 

 phere in the relative level of the land and sea bottom, 

 so that a quantity of coarse gravelly matter, appa- 

 rently the debris of some sandy or granitic rock, was 

 more or less abundantly deposited. This sand some- 

 times reposes conformably and evenly on the upper 

 coal grits, which pass into it : at other times the 

 upper surface of these latter beds has previously un- 

 dergone much wearing and grinding away, and occa- 

 sionally the lower beds, originally horizontal, have 

 been tilted up at various angles to the horizon, and 

 the upper ones removed before the newer sandstones 

 were placed upon them. 



Notwithstanding the turmoil and agitation which 

 marks this movement in some districts, it is yet cer- 

 tain that the disturbances began by small and com- 

 paratively unimportant changes of elevation, occurring 

 at intervals and at distant points, so that the general 

 aspect of submarine life, as known by the fossils found 

 embedded, was scarcely so far altered as to require 

 the introduction of any distinct groups. 



