STATE IIORTICULTUKAJ. SOCIETY. 125 



transported :iud roforined the soils to such an extent as to well nigh destroy their sepr 

 urate characteristics and origins over large portions of Northern Illinois, and greatly 

 increase the difticulty of their proper classitication. This force, whether Hoes and 

 bergs of ice, loaded with stones, gravel and detrital matter, and borne along l)y winds 

 and currents, or strong, earth-born water torrents, moving along and wearing the 

 abraded materials, or the slow procession of the all-powerful, crawling glacier — what- 

 ever it was, it moved like a vast army of shovelers, multiplied millions of tons of the 

 loose materials denuded and worn down from the rocks of the North, and piled them 

 like a thick earth mantle over the coal basins to the South and West. 



Of that great force I propose now to speak. In order to understand what I shall say, 

 it will be necessary to refer to the well-known action of ice and snow in the glaciers of 

 the Polar world. I have already shown that the struggle of the rain drop to get back 

 to its mother the sea, produces the silent, peaceful agencies and energies of nature, of 

 which I have briefly spoken. I propose now to show that the struggle of the snow- 

 flake to get back to its mother, the same sea, produced those mighty drift forces whose 

 results are so evident around us. 



Agassiz, Tyndall, Forbes, and other trustworthy scientific travelers, have made us 

 familiar with the action of the ice forces as they now exist in the Alpine glaciers. 

 Away up in the mountain basins of the Alps snows accumulate in vast fields and in 

 great thickness. When the mass becomes heavy and thick, pressure changes the bot- 

 tom of the mass into a plastic, porous sort of ice. This basin is the Mer Je Glace, or 

 sea of ice. Inasmuch as snow is constantly being added to it, the volume and thickness 

 of this sea of ice would soon become so great as to produce serious consequences if 

 some safety ^alve was not found to aflbrd vent to the pent up mass. The lower part 

 takes upon itself a slow, almost imperceptible, motion, and soon fills the descending 

 valleys with a stream or river of ice. As snow is added at the top, it sinks down to the 

 bottom, and when it becomes ice, is drawn ofi', as rivers run out of lakes. This ice 

 I'iver flows slow, but is subject to all the laws of flowing water. It widens, it contracts, 

 it deepens where the flow is slowest, and its motion increases where the mass passes 

 over rapids. As it crawls down in its slow, irresistible motion, dirt bands are formed 

 along its margins, stones and great masses of rock roll down upon it, the bottom and 

 sides of the cliannel are grooved, planed and striated by the mighty power of the grind- 

 ing, rubbing ice, and all the material accumulated is carried eventually to the lower 

 end of the glacier, and there dumped oil' in terminal mouraines and huge piles of 

 gravel, boulders, and other drift materials. In the case of the Alps, the glaciers melt 

 when they reach the plain and before they find the sea, and glacier-born torrents begin 

 where the ice ends, and the materials borne thither by the ice are further moved and 

 assorted by the muddy, rushing waters which take their place. The struggle of the 

 snow-flake has ended, and the struggle of the rain-drop now begins. Both are trying 

 to get back to their mother, the sea. It is true the ice river flows infinitely slow, but 

 in comparison with the river of water it moves infinitely strong. The Mississii)pi, if it 

 Avere a glacier instead of a water river, could bear upon its back bouklei's and whole 

 ledges of stone as readily as it now floats a feather or a saw log. What it lacked in 

 motion, it would make up in the slow. Irresistible and mighty force of its all grinding, 

 all consiuiiing procession. Such is a glacier in the Alps, and these glaciers arc knead- 

 ing certain parts of Italy over now as in past time they kneaded North America. 



Over the new Wrangells Land and in Greenland the same forces of the ice are in 



