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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stances, intervening between the exposures of the rocky beds. These
deposits vary very much in thickness, in the materials of which they are
composed and in the order in which their materials are arranged. No
two sections of Drift-beds can be found that will agree in every particular.
Before describing the leading characteristics of these beds, it will be
proper to call attention to an interesting fact that must be referred to
the same agencies by which the Drift itself is explained. Considerable
portions of the rocky surface of the county have been planed, polished,
striated and grooved by heavy masses of ice-inclosing sand, gravel and
boulders-moving over them. These phenomena can be best observed in
the firmer beds of the Niagara limestone, occupying as they do the highest table-lands of the county, but they are by no means confined to them.
The great belt of quarries south-east of Dayton, furnish fine exhibitions
of this agency. Indeed these naturally planed surfaces are frequently
turned to account for door-steps, flagging-stones and other similar uses.
It is altogether probable that the whole surface of the county has been
exposed to the abrading agencies of the glacial sheet, as we find the
marks of these agencies at every point where the rocks are firm enough
to retain them. The unconsolidated beds of the Niagara rocks have
been in large measure removed by the same force that has planed the
harder surfaces, as is evident from an inspection of those higher portions
of the system that still remain.
This polished surface of the Niagara rock is generally covered with
yellow clays intermingled with gravel and boulders. Sometimes heavy
granitic blocks have been left in the clay in almost immediate contact
with the bedded rock-their own surfaces having been planed and scored
by the service to which they have been put. We see in them the implements of abrasion-the graving-tools-left where the work was done.
The thickness of these clay deposits varies from 1 foot to 30 feet, and the
upper portions are almost always freer from gravel than the lower por~tions. Occasionally a limited deposit of blue clay is found on the surface
of the rocks, but for the most part these beds of blue clay when they
occur, are found overlying yellow clays or beds of gravel, in pockets of
small extent. Fragments of drifted coniferous wood are sometimes
found buried deep in these deposits.
Next in importance to the yellow clays are the beds of sand and gravel
of which the Drift-beds are largely composed. They sometimes overlie
the clays-are sometimes interstratified with them, and sometimes they
repose directly upon the surface of the rocks. The gravel contains representatives of all the formations that are found to be northward within
the limits of the State,-viz.: Blue Limestone, Clinton, Niagara, Water
Lime, Corniferous and Black Slates, and a considerable part of it is derived from the metamorphic rocks of the Lake Superior region and from
10-G. S.