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THE POPULAR SCIENCE MONTHLY. 



but ice gathered in little fragments which will grow solid under 

 pressure. As the snow accumulated it began to move, forming 

 great rivers of ice which ran down the courses of the streams. 

 And as these slowly moving, gigantic ice-rivers tore away huge 

 blocks of lava and pushed them down the mountain-sides, where 

 the rocks had been softened by the action of steam, the ice wore 

 out deep valleys, and everything that it touched was smoothed and 

 polished. The winter of the great Ice age lasted a very long- 

 time, many thousands of years ; but, long as it was and long ago, 

 it came at last to an end — not to a full stop, of course, for even 

 now some of its snow still lingers on the highest peaks that sur- 

 round the lava-beds. 



Then the winters grew shorter and the summers longer. The 

 south winds blew and the ice melted away, first from the plain 

 and then from the mountains. The water ran down the sides of 

 the lava-bed, cutting deep gorges or canons, so deep that the sun 

 can hardly see the bottom. And into the joints and clefts of the 

 rocks more and more water went, to be hurled back with greater 

 and greater violence, for all the waters of all the snow can not put 

 out a mile deep of fire. 



In the old depressions where the ice had chiseled away the 

 softer rocks there were formed lakes of the standing water, and 

 one of these was more than thirty miles long, winding in and 

 out among the mountain-ridges. In the lake bottom the water 

 soaked through down to the hot lava below, from which it was 

 thrown boiling back to the surface again, fountains of scalding 

 water in the icy lake. 



The cold Ice age had killed all the plants in the region ; it had 

 driven oif the animals that could be driven, and had then buried 

 the . rest. But when the snow was gone the creatures all came 

 back again. Grass and meadow-flowers of a hundred kinds came 

 up from the valleys below. The willow and the aspen took their 

 place again by the brookside, and the red fir and the mountain 

 pine covered the hills with their somber green. The birds came 

 back. The wild goose swam and screamed, and the winter wren 

 caroled his bright song — loudest when there seemed least cause 

 for rejoicing. The beaver cut his timber and patiently worked at 

 his dams. The thriftless porcupine destroyed a tree for every 

 morning meal. The gray jay, the " camp-robber,"' followed the 

 Indians about in hope that some forgotten piece of meat or of 

 boiled root might fall to his share ; while the bufi'alo, the bear, and 

 the elk each carried on his afl'airs in his own way, as did a host of 

 lesser animals, all of whom rejoiced when this snow-bound region 

 was at last opened for settlement. Time went on. The water and 

 the fire were every day in mortal struggle, and always when the 

 water was thrown back repulsed, it renewed the contest as vigor- 



