106 PICTURESQUE SKETCHES 



The nature of the remains of fishes found in the 

 magnesian limestone rocks indicates also a diminu- 

 tion in the size of the prevailing species, perhaps 

 arising from the gradual diminution and increasing 

 distance of the land, and the deepening of the sea 

 in the district where such remains occur. 



The reptilian fishes remain indeed, but they also 

 become small : those of the shark tribe are few, and 

 exhibit some peculiarities of structure, but are com- 

 paratively unimportant ; and the rest were chiefly the 

 bad and slow swimmers, or bottom fish, living on offal 

 and on the invertebrated groups. 



But a time of much greater change was approach- 

 ing a time of disturbance, which should shake to 

 their foundations all the solid and massive rocks that 

 had been then deposited ; and of subterranean move- 

 ments, which in their course should break asunder the 

 hardest and the strongest among these rocks ; crush- 

 ing and grinding into small fragments whole strata that 

 had become compact and closely consolidated, and 

 crumpling into complicated folds the toughest and 

 most unyielding beds, as if they had been layers of 

 some soft material carelessly squeezed in the grasp 

 of a powerful hand. 



It is indeed impossible for words to express the 

 complication of disturbance, or the amount of confu- 

 sion, that has been produced in some districts by forces 

 acting on the solid crust of the globe, between the 

 close of what we have called the first epoch, and the 

 commencement of the second ; and yet all this was done 

 with a certain degree of order, and doubtless occupied 

 a long period of time. Volcanic eruptions have taken 

 place in some districts, and their effect is seen in tor- 



