182 BOARD OF AGRICULTURE. 



furrows. You have here, then, a combination of circumstances 

 which explains the simultaneous formation of polished surfaces, 

 grooved, scratched, and furrowed, and the formation, over 

 these surfaces, of materials which have pressed against one 

 another, occasionally turning in their sockets, changing their 

 surfaces of abrasion, and thus becoming polished, grooved, and 

 scratched ; but the materials are so set that they do not change 

 their positions in a way to bring the heavier to the bottom and 

 the lighter above, or to impart to them anything like a regular 

 stratification. 



This is what is going on underneath a glacier ; and I can add 

 that I have seen the bottom of a number of glaciers, and I have 

 found there a kind of paste (made up of loam and sand,) 

 coarser and finer gravel, pebbles of all sizes, and boulders 

 of all sizes, rolled up together, and mingled in a confused way. 

 Occasionally, a large mass of rock, will separate from the soil of 

 the mountain, fall on the ice, and remain on its surface, and as 

 the glacier moves, that boulder is carried along, remaining on 

 the surface of the ice, and undergoing no abrasion ; rubbing 

 against nothing, but being carried smoothly along, while all this 

 grinding is going on underneath. Now, suppose for a moment 

 that the glacier melts away, what will be the consequence ? 

 This accumulation of loose materials, put together pell-mell, 

 remain where they are, and these large angular masses, which 

 have been carried on top of them, rest on these loose materials, 

 but do not sink to the bottom with them. We have, then, such 

 an accumulation of loose materials as we actually observe in 

 the drift ; the mass of the drift being a conglomerate of all 

 kinds of materials, mixed indiscriminately together, and on top 

 of them rest these large angular boulders. 



This, in itself, would be sufficient to satisfy a skeptic that 

 there is some foundation for considering glaciers as the possible 

 cause of the transportation of materials like drift, but I should 

 like to carry the comparison a little further, and to show you 

 a little more fully that there can be no other cause so active as 

 this, and that we have, in the fields of ice of our northern 

 latitudes the true cause of the transportation of our drift, and 

 of the grinding by which it has been brought into its present 

 condition. 



