38 GEOLOGY OP OHIO. 



underlying older Drift deposits by a carbonaceous layer, or old soil , which 

 shows that it was laid down on a submerged land surface. Whether this 

 soil corresponds to our Ohio Forest Bed remains to be proven, but it seems 

 highly probable that they are continuous and identical. Dr. E. Andrews 

 states that the Loess covers the upper ridge at the head of Lake Michi- 

 gan, and he infers that the water from which it was deposited was rap- 

 idly withdrawn, as otherwise it would have been washed from exposed 

 points from shore waves, and its continuity be broken by beach lines. 



BOWLDERS. 



The bowlders, or erratic blocks, as they are sometimes called, which are 

 scattered over so much of the surface of the State, have attracted the at- 

 tention and excited the wonder of most of its inhabitants. They are 

 usually composed of some kind of crystalline or metamorphic rocks, 

 such as are foreign to the geology of Ohio, and were on that account 

 recognized, even by the unlearned, as foreigners which had been brought 

 fro^u a distance and strewed over the surface or perched upon declivities 

 in some incomprehensible way. Though greatly varying in quantity in 

 different localities, the bowlders may be said to be common to all parts 

 of the State, except the highlands which have been specified as lying 

 outside of the Drift area or which rose beyond the reach of the agent or 

 agents by which the distribution of the Drift material was effected. In 

 the valley Drift of the channels of the Miami, Scioto, Muskingum, and 

 even the Ohio,, bowlders are exceedingly common, but they are never of 

 large size, and are only such as have been washed down by river cur- 

 rents from their original places of deposition; and these grow smaller, 

 and smaller as we descend the valleys in which they are found. 



Some of the bowlders distributed over Ohio are of immense size, and 

 some may be found in almost every county which have attracted special 

 attention. We have space to enumerate but few of these. In Montgom- 

 ery county, on the hill near the Soldiers' Home, is a partially buried, 

 rounded mass of gray granite, twelve feet in diameter horizontally, and, 

 as shown by execavations, not much less vertically. This would give 

 a bulk of 904 cubic feet and a weight of 75 tons. In Harrisville, Me- 

 dina county, are three blocks of granite, which were, apparently, once 

 parts of the same mass. The exposed portion of one of these measures is 

 10x12x15 feet. This would give a weight of about 150 tons for what is 

 seen only of this block. Another shows a corner projecting seven feet 

 above the ground, of which the three triangular faces measure respect- 

 ively 12, 15, and 12 feet along their bases. In the valley of Black 

 river, in Huron county, above Monroeville, is a block of Corniferous 



