296 



of the Peninsula. The largest masses of these were found near the 

 summit of the great dividing ridge, on its ea^itern declivity. Several 

 masses in the town of Somerset, Hillsdale county, are of such extent as 

 to be easily -mistaken for rock in place; portions only, being visible 

 from beneath the imbedding diluvium. I became convinced, however, 

 by the associated fossils, that they beh^ng to an older formation than the 

 carboniferous rocks of the vicinity. 



Boulders of this rock are so numerous in some parts of the country 

 as to afford almost the supply of lime needed for the district 



Masses of native copper, some of several pounds weight, have beeE 

 found in Berrien and Cass counties, as also in the Valley of Grand River, 

 and in several other portions of the State. These belong also, to the 

 "erratic group," and are no evidence of the existence of the ore in their 

 immediate vicinity. 



The same remark will apply to the pieces of bituminous coal found 

 very generally, through certain districts, imbedded in the diluvium. 

 Though they may be found at various depths and in considerable quan- 

 tities, no prospect can hence be inferred of finding coal beds in any of 

 the counties embraced in this report. 



SPRINGS AND UNDERGROUND WATER-COURSES. 



The character of the diluvial stiata is so varied over different districts, 

 and the formation of surface so diversified, (which might give origin to 

 springs under every variety of circumstances,) that it is impossible to 

 establish any general rule governing the depth and directions of under- 

 ground water-courses. 



Water from the diluvial deposits is usually obtained in strata of quick- 

 sand or gravel, at varying depths. But after ascertaining the general 

 characteristics of the surrounding country, some judgment may be form- 

 ed over particular districts. 



A stratum of quicksand producing water, is very generally found im- 

 mediately overlying the clay deposits. In the blue clay, ac the depth 

 of twelve to twenty feet, a sti-atum of gravel, yielding a suj^ply of wa- 

 ter, appeal's to be almost universal. 



Owing to the calcareous matter contained in the diluvial gravels and 

 sands, as well as in the clays, the water of wells is commonly '"hard." 



