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.

13
so their debris forms a calcareous mud; that which is known to sailors
as ooze, and such as is brought up on the lead in all deep sea soundings.
Now it will be evident that when the sea invades the land each of these
belts will be extended inland; the sheet of sand and gravel reaching
continuously as far as the submergence progresses, the finer mechanical
sediments nearly, but not quite, as far and overlapping the first; the
organic sediments being deposited above the others and only in the open
sea, or where it receives but little wash from the land. These strata,
which we have thus seen forming, when consolidated by pressure, heat,
and the deposit of soluble silica or carbonate of lime, are conglomerate
from gravel, sandstones from sand, shale from clay, and limestone from
ooze. In just this way all the sedimentary rocks have been formed.
In the State of Ohio, the first of the series of strata deposited on the
old sunken continent, is not visible-as it is covered and concealed by
those which overlie it-but going northward to the Canadian highlands,
or the Adirondacks of New York, we reach portions of the old continental surface which, as I have said, have never been submerged. Here
the series is complete; the lowest, and that resting on the crystalline
rocks, being a sandstone named the Potsdam sandstone. Above this
occurs the formation, composed for the most part of a mixture of lime,
sand and clay, called from this fact the Calciferous sandrock. Over this
again lies the great group of limestones, of which the Trenton limestone
is the most conspicuous, and therefore called the Trenton group, which'
includes the Blue limestone, the lowest stratum exposed in the State of
Ohio.
From what has been said it will be apparent that these three groups
of Lower Silurian strata are the products of the first invasion by the sea
of the old continent. Each of them forms a sheet underlying the entire
valley of the Mississippi. Of this-we have evidence, not only in what,we see in the Ozarks and Alleghanies-that have been upheaved in such
a way as to bring up and expose the older rocks-but also in borings
made at St. Louis, Louisville and Columbus. In all these wells the older
Silurian rocks have been reached. Our Ohio well was sunk to a depth
of 2,775 feet 4 inches. I am thus accurate because I was once called
upon to report upon' the probability of getting from the well the hoped
for artesian'flow of water. The boring was discontinued, perhaps at my
suggestion, as it seemed to me that the structure of this portion of our
State was not favorable to a flow of water to the surface, and as proved
by the observation of Dr. Wormley, the temperature of the well at the
bottom was,91 degrees-that of our hottest summer weather. The water
was also salt. Hence had a water-bearing crevice been struck at a
greater depth, the flow from it of hot and salt water could hardly have
been suited to the purpose it was intended to serve-the supply of the
State House and Capitol grounds.