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Page:Popular Science Monthly Volume 24.djvu/847

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827
GEOLOGICAL CHANGES IN MICHIGAN.

portance merits, and have been overlooked altogether by some geological writers, whose observations might be expected to cover their field. Let us take a look at this region and examine briefly some of the marks in which Nature has written its history. We find it in the main a sandy plain, wooded with white-oak, beech, maple, hemlock, and pine, varying in the proportion which they bear to one another, and interspersed with other trees and undergrowth in all the variety which the prolific flora of that region affords. In places the land sinks so low as to constitute a timbered swamp, and in others it rises to a moderate height above ground-water; often it appears, as indicated by the vegetation it bears, to be very fertile, but occasionally it is almost naked in its barrenness. Taken as a whole, it is of a lower degree of fertility than the heavier soils found in the more central and southern parts of the State, and for this reason it is less generally under cultivation than it otherwise would be.

This plain is, however, interspersed with tracts of land of a very different character. These consist mostly of a clayey loam, containing bowlders, as the sandy levels generally do not, having a more rolling and irregular surface, and, so far as it has been the writer's privilege to observe them, lying at a higher level than the sandy plain by which they are surrounded.

On scanning the map of Michigan, it will strike one as a peculiar feature of this west side of the State, that nearly every stream, large or small, that flows into Lake Michigan, expands into a small lake near its mouth, a fact that may have given rise to a query in some as to why such a peculiar feature should exist, especially in a country all of whose features are post-glacial—carved, indeed, out of the glacial drift or built upon it everywhere; and it is with the hope to throw some light on this matter, as well as other peculiarities of the region, that this article is written.

Our principal field of observation is the country near Whitehall, Muskegon County, Michigan, where the writer began to reside in the summer of 1878. This village is situated at the head of White Lake, on White River, which opens into Lake Michigan some six miles to the southwest.

In this river-lake one may see in many places an old water-line on piling, which at that time was at an elevation of three feet or more above the water. The fact that this line was continuous at a uniform level on lines of piling that were apparently undisturbed rendered the theory of uplifting by ice that was often given in explanation of it exceedingly unsatisfactory; and when old residents of the neighborhood were heard to speak, as they often did, of schooners loading and unloading, a few years before, in places where there was not at this time water enough to float a raft, it left very little room for doubt that this old water-line recorded a real change of relative level between the water and the land.