412 GEOLOGY OF OHIO. 



reports of the Survey. The latter is d»ubtless of much more frequent 

 occurrence. It is to a wide-spread stratum of interglacial vegetation that 

 the buried tree-tops, roots, leaves, and ancient soil, so often reported in 

 the digging of wells and other like excavations, must be referred. 



The Forest-Bed, as this stratum has been designated, is of much less 

 frequent occurrence in Preble county than in the counties to the south 

 and east of it, but there are still many evidences of its presence within 

 this area. In Harrison township a tree top is reported to have been 

 struck at a depth of thirty feet. 



An ochre seam, which, it will be remembered, sometimes accompanies 

 the Forest Bed and sometimes replaces it in the regions to the south- 

 ward, is also occasionally met with in Preble county. It is generally 

 found associated with a gravel seam, which it cements into a hard-pan, 

 which must be penetrated in order to reach the water veins. 



The beds of modified Drift, as the sand, gravel, and clay that overlie 

 the bowlder clay in stratified deposits are called, occur abundantly in 

 the county, not being confined to the deeper valleys, but being found as 

 well over most of the uplands of the county. In the northern town- 

 ships, and especially in the flat-lying districts, they have a general 

 thickness of about twenty feet, of which the following may be taken as 

 a representative section : 



FEET. 



Soil H 



Yellow clay streaked with bluisli clay 10 



Bhie clay (sometimes brown), always tine-grained, and free from gravel 8 



Underneath are found the seams of sand and gravel that cover the 

 bowlder clay, and which constitute the water-bearer of much of this 

 region. 



In all of the above named particulars the Drift of Preble county is 

 seen to be part and parcel of the great Drift field of Ohio, but there is a 

 single feature that remains to be mentioned in which it has preeminence 

 over all contiguous areas. A very remarkable bowlder belt traverses its 

 central and eastern regions — more remarkable than any similar belt 

 thus far reported in the State. There are various points in this general 

 region where bowlders are very thickly strewn over the surface for 

 limited areas, as, for instance, along the uplands that bound the Great 

 Miami Valley for twenty-five miles above Dayton, on the west side of 

 the valley, directly opposite Dayton, and also in the country that lies 

 west of the Stillwater, in the vicinity of Union, Montgomery county, 

 but none of these bowlder belts attain the proportions of that now under 

 consideration. 



Its northern boundary is not very distinctly defined, but there is a 



