FEKMUN AGE AND CLOSE OP THE PALEOZOIC. 185 



waters, and those wliica were born in the ocean depths, 

 The former spread themselves widely after every up- 

 heaval, and then by every subsidence were driven back 

 to their mountain fastnesses. The latter perished from 

 the continental plateaus at every upheaval, but climbed 

 again in new hordes and reoccupied the ground after 

 every subsidence. But just as in human history every 

 victory or defeat urges on the progress of events, and 

 develops the great plan of God's providence in the 

 elevation of man; so here every succeeding change 

 brings in new and higher actors on the stage, and the 

 scheme of creation moves on in a grand and steady 

 progress towards the more varied and elevated life of 

 the Modern World, 



But, after all, how little do we know of these laws, 

 which are only beginning to dawn on the minds of 

 naturalists ; and which the imperfections of our classi- 

 fication and nomenclature, and the defects in our know- 

 ledge of fossil species, render very dim and uncertain. 

 All that appears settled is the existence of a definite 

 plan, working over long ages, and connected with the 

 most remarkable correlation of physical and organic 

 change : going on with regular march throughout the 

 Palaeozoic, and then brought to a close to make room 

 for another great succession. This following Mesozoic 

 time must next engage our attention. 



We may close for the present with presenting to 

 the eye in tabular form the periods over which we 

 have passed. The table on page 187, and the 

 diagram (page 179), mutually illustrate each other; 



9* 



