Agasaiz at Penikete. 



crushed, would make loam and clay, and you have 

 iu some sections immense beds of soil without peb- 

 bles, which have been ground down by this all- 

 siuoothiug plane. 



You see, therefore, that we may have three kinds 

 of drift differing only iu respect to tho liability of 

 their components to be reduced to sand. Now I 

 would mention a few features very peculiar in 

 North American drift. These may be well observed 

 in the lake region of Western New-York, in the in- 

 numerable lakes trending north and south, with 

 their northern outlets and southern inlets. In all 

 the glacial phenomena are very plain. I have seen 

 them on Cayuga Lake. There you may see that the 

 sides of tho lake are well scratched and grooved, 

 and there is little doubt that the depression and 

 shapinis due to ice. Evidently there came a time 

 during the retreat of the glacier when this lake 

 region was fie southern extremity of the ice-sheet, 

 and formed many fiords exactly similar to those at 

 present indenting the coasts of Norway and Green- 

 land. But when the great ice-sheet presented these 

 fiords on its southern margin, they were covered 

 with lateral and terminal moraines, and at the 

 southern end of the lakes you have to this day con- 

 centric moraines just as you find them now in 

 Switzerland. One thing I want to impress upon 

 you : These indications are as plain as sign-boards. 

 It requires no imagination to find them, and you 

 must shut your eyes if you would not see. 



Now these moraines extend south at intervals, 12 

 of them, before you reach the hills from which the 

 lakes are now fed. The lakes are drained in a south- 

 northerly direction, and tho currents encroach and 

 react upon these moraines, tending to destroy the 

 appearance of their true origin. You may observe 

 these same phenomena in connection with all other 

 lakes in the northern half of our country. 1 have 



seeu them at dozens of lakes in Maine. 



*** 



Anybody who will study any of the road-cuts or 

 travel-pits, or make observations as he rides along 

 in the cars, may satisfy himself of alternate bauds 

 trending north and south, consisting of clay, &c., 

 more or less wide in accordance with the geological 

 constitution of the region to the north of them, 

 whence the drift came. You have in every one of 

 these bands, both material from the starting point, 

 and material gathered up by the way. Ice as it 

 moves along will take up and imbed in itself much 

 of the looser material it passes over. I have been 

 repeatedly under Alpine glaciers, and seen them 

 paved underneath with rocks, large and. small, which 

 are all the time grinding over the surface like a 

 huge file. These materials, frozen into the glacier 

 known as " bottom drift," may turn and get 

 scratched in every direction, but the surface below 



will only get scored in the general direction of mo. 

 tion. 



These bands may be one or twenty miles wide, or 

 only a few yards. One locality has loug been 

 known, and yet has remained a puzzle the " Rich- 

 mond Bowlders" in Western Massachusetts, where 

 you have seventeen or more parallel ridges trending 

 from north to south. To the north of Richmond 

 are three ranges of hills running east and west, and 

 at right angles to them these seventeen ridges trend- 

 ing southward. These ridges are made up of bowl- 

 ders from the different hills, all of which can be 

 traced back twenty miles or more to the three 

 ranges of hills. It has been a puzzle, because the 

 transportation of this great mass of material was 

 supposed to have taken place on the back of ice- 

 bergs or glaciers. But our drift is bottom-drift, 

 which the ice-sheet picked up in its labored, grating 

 passage over the three ridges that stretched across 

 its path north of the town. It is only a special case 

 of the general law by which bottom-drift is carried 

 over all inequalities under the glacier and is not 

 at all an exceptional feature, yet Lyell in his 

 Antiquity of Massachusetts makes a physical puzzle 

 out of it. Conceive seventeen rows of icebergs mov- 

 ing along in stately and well-ordered ranks, and all 

 dropping at particular points their load of rocks ! 

 These evidences are being gradually effaced in many 

 places by meteorological agencies. 



In the southern hemisphere you find exactly tho 

 same phenomena, but in reverse order. At Monte- 

 video I first observed the northern limit of glacial 

 action. There are rounded hills, truncated, pol- 

 ished, and shaped as no other agency ever fashions 

 them. There continue all along the coast of Pata- 

 gonia and through the Straits of Magellan the same 

 features which have been observed iu the northern 

 hemisphere ; but everywhere the direction is from 

 the south toward the north, from the Pole toward 

 the Equator. So that we cau no more doubt lhat a 

 great cap of ice covered the southern hemisphere 

 than that a similar cap spread over the northern. 



At Talcahuano in Chili a trend of scratches west- 

 ward toward the Pacific appears, and this seems to 

 confirm the fact that a great oceanic depression is 

 sufficient to influence the course of such a glacier 

 both as to direction and rapidity. 



The same facts which obtain in the northern ap- 

 ply as well in the southern hemisphere. Another 

 ndication I will mention. Whenever a hill stands 

 east- west, and slopes north and south, in tho northern 

 hemisphere, the northern slope is affected by the 

 glacier passing over it, but the southern slope is not 

 considerably. In the southern hemisphere tho 

 southern slope would of courae be the one roughly 

 used, while the north would escape. After passing 

 the Straits of Magellan, everywhere the eouthein 



