252 The Ohio Journal of Science [Vol. XXI, No. 8, 



in places, both horizontally and vertically. Not infrequently 

 they form pockets in coarse sandstone. 



In thickness the Sharon conglomerate also shows marked 

 variation due largely to the unevenness of its lower surface. 

 G. F. Lamb reports the maximum thickness of the rock in 

 northern Ohio to be 90 feet,^ while in the southern part of the 

 State, W. Stout records as much as 200 feet.- Thicknesses in 

 excess of 50 feet are common in Trumbull, Geauga, Portage, 

 Summit, Jackson, and doubtless in other counties. As a rule, 

 the rock is poorly cemented and hence is easily crushed. Silica 

 appears to be the chief bonding agent. The rock is massive 

 and cross-bedding is common. 



The base of the Sharon conglomerate is very uneven. 

 Before it was deposited the underlying Mississippian rocks 

 were extensively eroded and valleys 200 feet in depth were 

 formed in places. Lamb states that in northern Ohio the 

 Sharon is restricted to these valleys and that they have a 

 north-south trend.'' On such a surface the Sharon was deposited. 

 The irregularity of this contact in the central and southern 

 part of the State is well shown on Plate III of Bulletin 21, 

 Geological Survey of Ohio. It forms the most striking uncon- 

 formity in the State. 



In northeast Ohio, all of the Mississippian above the 

 Cuyahoga appears to have been removed by erosion, and the 

 Sharon, therefore, rests directly on the Cuyahoga. In the 

 central and southern part, however, the Sharon lies in many 

 places on the Maxville limestone, the top of the Mississippian 

 strata.^ This indicates that before the Sharon was laid down 

 there was more extensive erosion of the Mississippian rocks 

 in the northern part of the State than there was in the southern 

 part. 



From what has been recorded concerning the thickness and 

 length of outcrop of the Sharon in Ohio, it is apparent that the 

 quantity of rock is enormous, and regardless of what use may 

 be made of it, the supply is ample for centuries. Brief descrip- 

 tions will now be given of the principal plants, and data on 

 the chemical and mineralogical composition of the sand. For 



1 Personal letter dated August 30, 1920. 



2 W. Stout, Bull. 20, Geol. Survey of Ohio, p. 42. 



3 G. F. Lamb, Jour, of Geol., Vol. 19, p. 105. 

 * W. Stout, Bull. 20, Geol. Survey of Ohio. 



