THE ICE AGE. 325 



In the West the same tale is repeated. Throughout Ohio, bowl- 

 ders are found which are composed of rock utterly foreign to their 

 present surroundings ; indeed, of material not known within the limits 

 of the State. These are found perched over declivities, buried in the 

 soil with their exposed edges showing above the surface, or else lying 

 unencumbered in slight depressions of the ground. In Indiana, 

 Michigan, Illinois, Wisconsin, etc., they are omnipresent, and the 

 streets of Cincinnati are paved with the smaller specimens that 

 crowd in exhaustless trains upon the footsteps of their larger com- 

 panions. In short, we gather the irrefragable testimony, wherever we 

 look for it, through our Northern States, through Europe and Asia, 

 and even along the western coast of South America, that some im- 

 mense force has been exerted in times past, not only to dislocate and 

 shatter the rocky barriers which opposed it, but also to carry away 

 the evidences of its ravages, and scatter them in its southward 

 movement far removed from their place of origin. Further, let it be 

 remarked that, though one class of these erratics is composed of angu- 

 lar and unworn stones, another yields bowlders that have undergone 

 severe attrition, and along their larger axes are striated and polished ; 

 bearing in mind, moreover, that the direction of their transit coin- 

 cides with that of the furrows and flutings in the same region, we 

 may strictly conclude that they are a feature also of the same exces- 

 sive and gigantic system of erosion. 



But there is another appearance which we believe vitally con- 

 nected with these, and one of a yet broader and more significant char- 

 acter in its general relations than they are. Over Scotland, England, 

 Ireland, Scandinavia, Denmark, Central Europe, Switzerland, Russia, 

 France, Spain, and in North and South America, in short, wherever 

 we discover bowlders and grooved surfaces, we find a deep and char- 

 acteristic deposit, not the work of alluvial formations or recent detri- 

 tus, for it underlies these, but the record of a vast disintegration 

 which, having planed and corroded the continents, has covered the 

 land with sheets of gravel, clay, silt, and sand, all intermixed with 

 stones and bowlders, variously combined in their order of succession, 

 and ranging in depth to over 300 feet. These immense beds furnish 

 gravel for roads and ballast, sand for glass-making and mortars, and 

 clay for pottery; their included stones and fragments are scored 

 and embroidered with fine and interlacing stria?, and they cover the 

 furrowed surfaces of either hemisphere for miles. 



They represent the accumulated w T ear and tear of continents, 

 under some extraordinary agent of erosion and denudation, whose 

 teeth have resistlessly ground upon the solid rocks of the hills and 

 highlands, hiding disfigured surfaces beneath a covering of ruin. 

 Long Island is itself but one long dirt-heap : an accumulated pile of 

 continental debris, sand, clay, gravel, intermixed and overlaid by 

 bowlders, is here gathered together into a more or less stratified state, 



