204 THE PHENOMENA OF DRIFT, OR 



6. Detritus of Moraines. 



If currents of water were concerned in the production of mo- 

 raines, as we have supposed, we should presume, that as the ice 

 mehed away, those currents would often change their direction, 

 so as to wear away the moraines, and deposit their ruins in other 

 places. Of course these new deposits would be stratified ; be- 

 cause the materials would be sorted by the water. And as the 

 minor currents would be much deflected among masses of ice 

 and iiTegular hills, we might expect cross and contrary currents, 

 producing iiTCgular and inclined lamination. Accordingly we 

 find that much of that detritus which we must refer to glacio- 

 aqueous agency, originally, exhibits such stratification and lamina- 

 tion as have been described. And such re-arranged materials 

 have been appropriately called the Detritus of Moraines. A 

 section of such moraines will give a perfect idea of them. Plate 

 VIII, fig. 11, shows one in the town of Uxbridge, two miles 

 south of the principal village, on the road to Providence. It is 

 five rods long, and eight or ten feet high. The materials vary 

 from coarse gravel to common sand. 



7. Deposits of Clay and Sand. 



If drift was borne and driven along by masses of ice, as we have 

 supposed, we should expect to find it accumulated in the vicinity 

 of narrow gorges : and there in fact we do find it, blocking up the 

 passage frequently, unless a river pass through the defile. In that 

 case we find the drift cut through to a great depth. Now this 

 excavation must have been a slow process ; and when it com- 

 menced, the stream must have been so much higher than at 

 present, as to throw back the waters where level regions existed : 

 in other words, numerous lakes and ponds would be formed at 

 the close of the drift period : and as we suppose the ice, whether 

 transported or accumulated on the surface, to continue for a long 

 time to melt, the streams thus 'produced would cany large quan- 

 tities of mud and sand into the basins above described, where they 

 would be deposited in the most quiet manner, in horizontal or 



