500 The Michigan Grayling. 



found are a few sandy eminences, — they can scarcely be called hills, — 

 the formation of which we leave the geologist to account for. And 

 yet the rivers abrading against these sand-hills occasionally cause 

 precipitous bluffs (few of which exceed a hundred feet), or such an 

 elevation as is known in a lumberman's parlance as a "roll-way." 



There is a gradual but almost imperceptible elevation from Bay 

 City or Grand Rapids to the region where grayling are found. From 

 the former to Grayling, where the railroad crosses the Au Sable, 

 a distance of nearly a hundred miles, there is a rise of seven hun- 

 dred feet, which gives the rivers an average current of about two 

 and a half miles an hour. Wherever there is a contraction in the 

 width of the stream, however, especially around a bend, its velocity 

 may be three, four, or even five miles, but on account of the absence 

 of rocks in the bottom, it almost invariably flows smoothly. The 

 strength of the current can only be seen where the ends of half- 

 sunken logs or " sweepers" project above the surface, or when the 

 canoeman turns his prow up-stream. 



The grayling region on the Lake Huron water-shed has a top 

 stratum of coarse white sand. On the streams flowing toward Lake 

 Michigan, the sand is yellow, with more or less admixture of vege- 

 table loam. The rains falling on these sandy plains and percolat- 

 ing through meet with a lower stratum of impervious clay, and 

 thus form under-ground courses which crop out at the margin or in 

 the beds of the streams and keep them at the temperature of 

 spring water. 



The eighth longitudinal line west from Washington may be 

 considered the apex of the water-sheds, declining East and West, 

 although the head-waters of streams occasionally interlock. By a 

 short " carry, " one can pass from the head-waters of the Manistee 

 to those of the Au Sable. I have seen marks on both of these 

 streams that gave evidence that surveyors did so forty years ago, 

 and have no doubt that it was a route used by the Indians in cross- 

 ing from Lake Michigan to Lake Huron. 



The country, except on the barrens, furnishes a fine growth of 

 white and yellow pine, as well as oak, beech, maple, and other 

 hard woods. White cedars — the arbor vitse of the East — invari- 

 ably fringe the banks of rivers a few miles below their sources, 

 which are generally in ponds or lakes. These trees appear to love 



