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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flowed out from crevices in the sandrock and become inspissated. The
places of outflow had exactly the same stratigraphical position just above
the Black Slate. On Bear creek, a tributary of the Scioto river, in Scioto
county, we found similar oil springs. Oil springs are found on the Kinnickinnick creek, in Kentucky, in the same geological position. No one,
after an examination of the various localities, can doubt that the oil
originated in the Black Slate. Other interesting facts tending to verify
this conclusion will be given in connection with the description of another
black slate desposit found interstratified with the Waverly sandstone.
There are occasionally found interstratified with the layers of slate
thin layers of asphaltum. They have a highly resinous lustre. They are,
however, very limited in extent, and appear to have spread themselves,
as if at one time they had been pressed out of the slate in a viscid condition.
In the Black Slate are often found septaria, or large concretionary
forms, which are generally hollow and contain crystalized calcite and often
shining globlules of asphaltum. Similar concretions in the Black Slate,
near Delaware, contain the remains of fishes of the most remarkable size
and form. No search has yet been made for these strange fishes in the
Second District, but scales of small ganoid fishes are abundant in the
slates, especially in the upper part.
Lingula sub.spatulata, M. and W.: Discina, capax? White, are also
found, the Lingula in great abundance. Careful search has been made
for other mollusca, but thus far in vain. Near Latham, on Sunfish creek,
Pike county, was found a stratum of very hard fire clay 1 ft. 2 in. thick,
situated fifty feet above the base of the black slate. This is the only
break in the continuity of the slate anywhere observed. It may be only
local, but it indicates that for a short time the waters in that region were
free from the usual organic matter, while at the same time they dropped
an exceedingly fine clay sediment.
Uses of the Black Slatc.-Oil is easily distilled from it, but the yield is
not large and such distillation will be unprofitable while the earth yields
petroleum so bountifully.
The slate, when burnt or pulverized, is said to answer an excellent purpose for roofing when mixed with coal-tar. Capt. James Patterson, of
Rockville, has prepared the material and it is said to be useful and durable. The slate is first de-bituminized by heat and afterwards ground into
powder to be mixed with the tar. The process of baking the slate has
hitherto been done in retorts. Should the slate be found capable of being burnt in open heaps,a great expense would be saved. There is no
limit to the supply of slate in the hills.
The slate is also used for covering walks in place of gravel. It rapidly
crumbles and covers the walk so compactly as to prevent the growth of