602 GEOLOGY OF OHIO, 



irregular, heterogeneous heaps. TJie former are indicative of the milder, 

 pains-taking action of water. The latter, of the more violent and reck- 

 less agents — glaciers and icebergs — -though it must be borne in mind, 

 that the regular, distinct laminations may frequently result from the 

 subsequent action of water upon the confused mass of glacial deposits. 



The constituents, origin, and causes of the Drift have been so re- 

 peatedly arid so exhaustively treated in Vols. I and II of the Reports of 

 the Ohio Geological Survey, that it is not necessary to enter into an ex- 

 tended discussion of them here. 



The various phases of the Drift formation are fully and, in a few places, 

 finely shown, but the structure is rendered, I think, somewhat more diffi- 

 cult to unravel, for the reason that the county lies at about the junction 

 of the two grand systems of forces acting from the region of the Lake and 

 that of the Ohio. There appears to b& no uniformity in the divisions of 

 the deposits, no two sections showing the same succession of parts. The 

 following section was obtained from the well at the Gas-works, in Green- 

 ville : 



wr. m. 



Sod and yellow clay - 6 



Eed clay 1 6 



Yellow clay, Tvith pebbles and bowlders . 8 



Yellow sand, stratified 8 



Hard-pan , - 1 6 



Fine blue clay, very tenaoiona — stratified 8 



Blue sand and gravel 21 10 



To.tal depth 42 



The beds all appeared partially stratified, while the pebbles and bowl- 

 ders were much water-worn. The thin layer of tenacious blue clay is 

 undoubtedly that derived from melting icebergs, the running streams of 

 which would naturally result in the stratification of the fine material. 

 The surface bowlders consisted chiefly of greenstone, syenite, diorite, 

 etc. ; whilst in No. 3, we found many worn bowlders of water-lime and 

 Niagara limestone. One small glacial bowlder was taken up from No. 7. 

 Cyathophylloid corals, and several other of the ordinary Drift fossils, 

 were common. 



Prom numerous other wells, of a greater or less depth, the following 

 typical section might be noted : 



IN. FT. 



Sod or loam From 6 to li 



Eed clay " to 4 



Yellowclay "12 to 15 



Yellow sand and gravel " 6 to 20 



Blue sand and gravel " 8 to 'iO 



