422 | GEOLOGY OF OHIO. 
On the opposite side of the creek, and a mile or two further down, there 
is a still more extended section of the same elements. It is found on the 
farm of the Roberts’ brothers. It does not deserve to be called a new ex- 
posure, as the outcrop of the rock is scarcely interrupted from one point 
to the other. : 
A somewhat anomalous fact meets us in this section. There is inter- 
polated in the Corniferous series a few inches of a very pure, saccarhoidal 
sandstone. The occurrence of such a deposit at about this point in the 
scale is not, however, named here for the first time. Rev. H. Herzer 
reported several years since a similar deposit in the Corniferous at West 
Liberty, Logan county, and Mr. Franklin C. Hill, in his report for the sur- 
vey on this county, shows that sandstone holds the same relations there 
that it has in Madison county. It is not found at the base of the Cornifer- 
ous series in either instance, but it occurs inthin beds distributed through 
five or more feet of the limestone at an elevation of about fifteen feet 
above the base of the series. It is underlain by undoubted beds of Corni- 
. ferous limestone and can not therefore, in these instances, be considered — 
as the southward extension of the Oriskany sandstone. It is rather the 
counterpart of the Hillsboro sandstone which, in like manner, is inter- 
jected into the Niagara series—in the southern part of the State. These 
two aberrant sandstones furthermore agree very closely in lithological 
characters. 
The sand from the Roberts quarries has long been known throughout 
the adjacent country and has even found its way as far as Columbus.. 
Whenever plastering of unusual excellence is attemptedin this vicinity, 
recourse is had to this deposit. The sandstone is nowhere more than six 
inches in thickness and it lies between ledges of rock so heavy that it 
ean not be profitably obtained except when the quarry is worked for 
other purposes. Its interest, in other words, is geological rather than 
economical. | 
These are the only known localities in Madison county in which the 
bedded rock is exposed to view. On the extreme eastern edge of the 
county, in Jefferson township, it has been ascertained in the driving of 
wells that the rock lies about forty feet below the surface. There area few 
other points in the county in which the underlying rocky floor has been, in 
like manner reached, but these cases are of very rare occurrence. Borings 
of fifty or even sixty feet are often made which do not exhaust the drift 
beds. : 
There is no region of the State in which the basement rock makes a 
more insignificant show or exerts less influence upon the present sur- 
face of the country. Even the details of the topography are seen to 
