62 TOWN GEOLOGY. [n. 



But still, they may have been rolled hither by 

 water. That theory certainly would explain their 

 being rounded; though not their being scratched. 

 But it will not explain their being found in the clay. 



Eecollect what I said in my first paper : that water 

 drops its pebbles and coarser particles first, while it 

 carries the fine clayey mud onward in solution, and 

 only drops it when the water becomes still. Now 

 currents of such tremendous violence as to carry these 

 boulder stones onward, would have carried the mud 

 for many miles farther still ; and we should find the 

 boulders, not in clay, but lying loose together, pro- 

 bably on a hard rock bottom, scoured clean by the 

 current. That is what we find in the beds of streams ; 

 that is just what we do not find in this case. 



But the boulders may have been brought by a 

 current, and then the water may have become still, and 

 the clay settled quietly round them. What ? Under 

 them as well as over them ? On that theory also we 

 should find them only at the bottom of the clay. As 

 it is, we find them scattered anywhere and everywhere 

 through it, from top to bottom. So that theory will 

 not do. Indeed, no theory will do which supposes 

 them to have been brought by water alone. 



Try yourself, dear reader, and make experiments, 

 with running water, pebbles, and mud. If you try for 

 seven years, I believe, you will never contrive to make 

 your pebbles lie about in your mud, as they lie about 

 in every pit in the boulder clay. 



Well then, there we are at fault, it seems. We 

 have no explanation drawn from known facts which 

 will do unless we are to suppose, which I don't think 

 you will do, that stones, clay, and all were blown 



