The Prescott daily news., 1908-06-27
TORRENTS FROM MELTING ICE DRAINED THROUGH GREAT
 LAKES TO THE STREAMS.
OLD BOUNDARIES ARE TRACED
Expert Wright Tells Where the Work of the Prehistoric Period Orig mated and Ended-Bodes
 of Water Eniarued.
BY G. FREDERICK WRIGHT, A.

Author of ''The Ice Age in North Amer
 ca,' Man and the Glacial Pe-
 riod." Etc.)
 Copyright, by Joseph B. Bowles)
 Ice is a rock. At any rate, so long as 1t lasts 1t performs all the functions of rock. As one steams up the Yukon river he will often see ahead of him forest growing upon high bank with precipitous face which at first sight would seem to be the enduring rock of the region. But upon near ap. proach it will turn out to be an ice cliff covered with a few feet of soil which has been washed out upon it in sufficient quantity to support vegeta- ton. Large forests are growing upon the Malaspina glacier in Alaska, sev- eral miles back from its front and where the ice is 1000 feet thick under it. In numerous places in the vicinity of existing glaciers large streams of water may be found running both upon the surface of the ice and along a high elevation between the ice and the adjoining highland or mountain chain which hens it in. Large lakes
  tions where they are held in by ice barriers. Where these barriers sud- denly burst through. as they some times do, tremendous floods of water devastate the valley below The Matt, mark See, in Switzerland, and other bodies of water held up behind alpine glaciers have been a menace.
 nuf upon the drainage, of ice of existing glaciers, those brought to light by study of the glacial period in North America surpass them all in wonder full measure. Naturally the accumula- tion of ice during the glacial period began at the north, and early clogged up the great lines of drainage which lead in that direction, while, after the ice had reached its farthest limit and began to melt back. the northerly di- rection of the drainage could not be resumed until the ice had all melted away. Thus for long periods the drain. age of the great lakes, which now passes down the St. Lawrence river, was turned over to swell the volume of the Susquehanna and the Ohio rivers. while all the drainage that now enters Hudson bay was turned over into the valley of the Missouri and the Mississippi This, anyone can see from slight study of the map, must have been the case. It has been a most interesting work to geologsts to find these actual outlets of glacial drainage, and to trace the effects of this great addition of volume to the south-nowing streams of the north.
 In general the effects of this great increase of the volume of the water poured into the valleys of the con- necticut, Hudson, Susquehanna, Ale gheny. Ohio. Mississippi and Missouri rivers are evident in the extensive gravel terraces which line the banks of all these streams and of their northern tributaries.
 The terraces of the Connecticut river have long been famous, consist ing of deposits of gravel and sand ris- ing upon either bank of the river from 50 to 100 feet or more above present high water mark. In the Hudson val ley they exist as brick clays, extensive ly worked in various places above New York city. but spreading out into extensive gravel deposits where the Hudson river comes out from the Adirondack mountains. The sandy plains of Saratoga were spread out during that stage of the glacial period,