Geology . er than it would be otherwise, and some-times so as to give it less relief. This is illustrated by Figs. 478and 479. (c) The drift is measurably independent of present drain-age basins, so far as its constitution is concerned. Thus, materialsfrom one drainage basin are found in the drift of other drain-age basins so commonly as to make it clear that present divides didnot constitute divides to the ice. (d) Various sorts of material inthe drift at certain points are so related to their sources as to makeit clear that they were carried upwards, sometimes hundreds of feet,from their ori
Geology . er than it would be otherwise, and some-times so as to give it less relief. This is illustrated by Figs. 478and 479. (c) The drift is measurably independent of present drain-age basins, so far as its constitution is concerned. Thus, materialsfrom one drainage basin are found in the drift of other drain-age basins so commonly as to make it clear that present divides didnot constitute divides to the ice. (d) Various sorts of material inthe drift at certain points are so related to their sources as to makeit clear that they were carried upwards, sometimes hundreds of feet,from their original sites, a point which is often readily establishedin the case of large bowlders. Glaciers can do this sort of work, underproper conditions, but water, unaided by ice, cannot, (e) A con- ;;n GEOLOGY. siderable area in southwestern Wisconsin, and the adjacent parts ofIllinois. Iowm, and Minnesota, Is withoul drift. The driftless area1of these states is neither notably higher nor lower than its surround-. Fig. 478.—Figure to illustrate the disposition of the drift in such manner as toincrease the relief of the surface on which it lies. ings, and the agent which produced the drift must have been suchas could avoid this area. Glacial ice seems to be the only agent com-petent to the result. (/) Stratified drift often extends beyond theunstratified, in the direction in which the ice was moving, especially
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