20 The American Geologist. juiy, i89!i> 
and attributed l^y liim to a submergence occasioned by an ice-dam 
at Cincinnati, and those which cover the glacial drift further west. 
No essential diflference of any kind could be detected. In both 
localities the cla}' has a depth of 2 — 5 feet, is nearly free from peb- 
bles and coarse grains, and is usually so compact as to be almost 
impervious to water; sandy pockets occur in it, and there are 
places where the clay seems to graduate into a sand or fine gravel 
it also frequently exhibits indistinct lamination. Such pebbles as 
occur are either cherty or are of distant (mainly Canadian) deriva- 
tion, no limestones having been observed. The clay contains 
very little calcareous material. The absence of limestone pebbles 
and the small amount of calcareous material may, however, be 
due to removal by leaching subsequent to the deposition. Con- 
cretions of iron oxide are common and conspicuous features, 
occurring in the form of balls in all sizes from one-half inch or 
more in diameter down to barely discernible grains. The follow- 
ing result of a chemical analysis of the clay confirms the evidence 
derived from an examination of the coarse particles of the deposit. 
The analysis was made by T. Gr. Wormley, a chemist of the Ohio 
Survey, and the specimen is from western Highland county which 
lies within the glaciated district. It appears in the Geology of 
Ohio (Volume i, page 445) : 
Water combined 5.54 
Silicic acid 62.60 
Alumina 18.90 
Sesquioxide of iron 6.30 
Manganese 0.20 
Phosphate of lime 0.63 
Carbonate of lime 1.89 
Carbonate of magnesia 1.82 
Potash and soda 2.32 
Total 10010 
Specimens of the clays covering Beech Flats, in Pike county, 
Ohio, and of those covering the till in Highland county, 15-20 
miles back from Wright's glacial boundary, have been submitted 
to Prof. R. D. Salisbury for microscopic examination. He finds 
no essential diflference in the specimens. In l)oth situations they 
consist mainly of quartz grains, among which are feldspar frag- 
ments, hornblende and possibh' epidote and augite; there are also 
minute iron oxide concretions and coarse grains of chert. The 
material is largely angular, even when the grains are of sufficient 
size to have been liable to rounding under favorable conditions. 
