212 GEOLOGY. 



position, from its centre and summit. This accounts for 

 the great profusion of Silurian organic remains in that 

 neighborhood. Indeed, there is no locality which forces 

 upon the observer more strongly the profusion and rich- 

 ness of the early creation, for one may actually collect 

 the remains of Silurian shells and Crustacea by cart-loads 

 around the city of Cincinnati. A naturalist would find 

 it difficult to gather along any modern sea-shore, even 

 on tropical coasts, where marine life is more abundant 

 than elsewhere, so rich a harvest, in the same time, as he 

 will bring home from an hour's ramble in the environs 

 of that city." 



305. Scenery of this Age. During most of the Devo- 

 nian age the scenery must have been exceedingly tame 

 and monotonous. " Over dark and shallow seas," says 

 Hugh Miller, " mud-banks of vast extent occasionally 

 raised their flat, dingy backs, and remained hardening in 

 the hot sun until their oozy surfaces had cracked and 

 warped, and become hard as the sun-baked brick of 

 Eastern countries ; and then, ere the seeds of terrestrial 

 plants, floated from some distant island, or wafted in the 

 air, had found time to strike root into the crevices of the 

 soil, some of the frequent earth-tremors of the age shook 

 the flat expanse under the water out of which it had 

 arisen, and the waves rippled over it as before." And 

 when vegetation obtained any where a foothold upon the 

 land, as was the case quite extensively in the latter part 

 of the age ( 295), it was comparatively scanty, and 

 there was none, of that variety of surface which we have 

 now, for there were no lofty mountains nor large rivers. 

 Besides, there were no birds nor four-footed beasts to 

 enliven the scene. 



