316 



on the east and soutli side of tlio main ridge of the Peninsula, and may 

 be considered as a natural consequence of so considerable an obstacle as 

 this partial barrier must have interposed to the force of northerly cur- 

 rents. Here, wells have been carried to the depth of 90 feet, through 

 beds of stratified gravel. 



Throughout all the diluviums, thin local beds of clay are of frequent 

 occurrence, and occasional strata of hard pan or cemented pebbles. These 

 clays, unhke those of the tertiary, contain little or no lime. 



Most of the country thus covered by the diluvial deposits, exhibits the 

 action of strong currents and eddies, in a very striking manner. Dis- 

 tricts of many miles extent, frequently present a continued and close suc- 

 cession of rolling knobs or cones of gravel, with deep intervening ba- 

 sins. The more ordinary character of surface is a gentle roll or shght 

 undulation occasionally subsiding to a perfect plain. 



Except where a deposit of clay underlies, the growth of timber is al- 

 most invariably scanty, constituting what are denominated "oak open- 

 ings." The character of the timber changes with the varying conditions 

 of the soil, from white and black oak, to burr oak or hickory, and the 

 plains are frequently altogether destitute of timber. A dense growth 

 of the usual hard wood timber sometimes occurs over isolated tracts, in 

 swales, or along banks of streams. Of the character of country de- 

 scribed, are found the three most southei'ly ranges of counties, with the 

 exception of those which immediately border the Peninsula, on the great 

 lakes, together with parts of the adjoining counties, and the counties of 

 Ingham and Eaton. All the latter have a sub-stratum of clay, belong- 

 ing to the great deposit to be presently described, and in consequence 

 differ very materially in surface, soil, and timber. 



To this extreme thickness and comparatively loose texture of the dilu- 

 viums, may be ascribed the great abundance of springs, and consequently 

 of the small streams which irrigate the whole surface of the State, af- 

 fording abundance of that element so desirable to the farmer. An un- 

 dulating surface gives to most of these a sufficiently rapid flow to pre- 

 ser\'e a healthy current and to furnish a sufficiency of mill power. From 

 the same cause, also, little difficulty is experienced in obtaining pure wa- 

 ter by sinking of wells, and it may safely be said that Michigan is bet- 

 ter supphed with hving water, uniformly distributed, than any other 

 State in the Union. 



