Part I. Report of progress in 1869, by J. S. Newberry, chief geologist. Part II. Report of progress in the second district, by E. B. Andrews, assist. geologist. Part III. Report on geology of Montgomery County, by Edward Orton, assist. geologist.

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ductive Coal Measures. This is also the order in which they appear in
the district, as we pass from the western line eastward. Each of these
formations dip to the east and South-east, and they consequently overlie
each other as shingles upon a roof.
The general outlines of these several formations have been studied and
mapped. In the hilly region in the southern part of the State, it is most
difficult to determine the outlines with entire exactness, without much
longer time for the work than has yet been at my disposal. The general
outlines, however, are given, and more minute details will be added hereafter, as the several counties through which these lines pass are separately studied. As the Ohio river crosses the different formations,
careful determinations have been made of the points where most of the
formations show themselves on its banks, and dip beneath its bed.
The Conglomerate in my district is very uncertain. It is not often
found in its true place, and instead of constituting a uniform and widespread floor, on which the coal measures rest, it is found only locally,
being deposited where strong currents swept, while in the more quiet
waters of the period firmer grained sandstones were accumulated, which
I have provisionally called the Logan Sandstones. In the provisional
map of the outlines of the formations I have given a more continuous
Conglomerate than the facts will probably warrant, rather out of a sort
of geological courtesy and reverence for the " traditions of the elders"
than any other reason.
THE OHIO BLACK SLATE.
The "' Ohio Black Slate" is the lowest formation in the geological series
found in the 2d District. It is finely exposed, in Ohio river hills, in the
neighborhood of Rockville, Adams county, and in nearly all the hills
which range to the north. The upper part of it is well seen in the hills
at Chillicothe, underlying the Waverly Sandstone group. It spreads
itself across the Scioto valley in its upper part, and is found resting upon
the Corniferous limestone in the immediate vicinity of Columbus.
Thickness.-It was carefully measured by the barometer, in the Ohio
river hills, near the mouth of Big Sulphur creek, Green township, Adams
county, and found to be 320 feet in thickness. Here its limits were distinctly seen, as it rested upon the limestone-the "Cliff Limestone" of
Dr. Locke-and upon it reposed the Waverly sandstone. This formation
is probably less thick in its northern extension from the Ohio river,
although no measurements have been made. Prof. Orton, of the 3d District, who has observed the Black Slate on the waters of Paint creek,
west of Chillicothe, thinks the formation considerably thinner in that
region than on the Ohio river. Although only half as thick as the
Waverly, it often covers as much horizontal surface as the latter, some