18 The American Geologist. July - 1903 - 
doubtiess one of the sources of the material used by the ab- 
origines in the manufacture of implements and weapons, but 
was gathered by them mainly from the drift. 
Such material indicates in the waters of the Corniferous 
sea a considerable quantity of silica in solution and possibly 
a high temperature. The silicification probably began with the 
death of the organism and proceeded rapidly amid conditions 
resembling those of the Cretaceous era in Europe, but without 
the abounding infusorial forms of the latter. 
In some parts of the state a flow of salt water has been met 
at the base of the Corniferous limestone, but in the northeast- 
ern counties no such difficulty has been reported and several 
wells have been sunk to and through it, and for hundreds of 
feet below it, which have remained perfectly dry. It is prob- 
able that, in the former cases, a local bed of the Sylvania or 
the West Jefferson sands was encountered in which the water 
was stored, and which was at one time thought to represent 
the Oriskany. 
Local patches of fine white glass-sand occur near the base 
of the limestone, similar to some found in the uppermost 200 
feet of the Silurian series. These sands are remarkable for 
their purity and sharpness. This Corniferous sandstone out- 
crops in Jefferson township, Madison county, on the .bank of 
Little Darby creek, and there is every reason to believe that 
other pockets of it will be found in the vicinity. "It has long 
been known to the plasterers of the neighborhood. Whenever 
the finest quality of work was required, recourse was had to 
the thin layers of sandstone found in this section."* 
"The sandstone is nowhere more than six inches thick and 
it lies between ledges of rock so heavy that it cannot be profit- 
ably obtained except when the quarry is worked for other pur- 
poses." 
Deposits of a similar sandstone are also found in Madison 
and in Logan counties.! The comparatively unworn appear- 
ance of the crystals of these sandstones, their small extent and 
their singular occurrence in the midst of solid sheets of lime- 
stone of almost continental area, argue for them an origin dif- 
ferent from that of most sandstones. 
* Geology of Ohio, vol. iii, p. 615. 
• Ibid., p. 422. 
