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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tions made by the geologists of those States in different anl widely separated localities, had presented discrepancies that had given rise to long,
earnest, and, sometimes, bitter discussions. Before the diverse conclusions of these various observers could be harmonized, and the succession
and distribution of the rocks represented in our geology be fully made
out, it was necessary that these views should be compared in Ohio; that
observations made east, west, north and south should here be connected.
Ohio thus, in some sort, formed the key-stone in the geological arch
reaching from the Alleghanies to the Mississippi; and for many years
geologists in our own country and abroad, had been looking forward
with great interest to the time when the geological survey in Ohio should
supply this key-stone, and render our whole geological system complete
and symmetrical. It was also necessary that our work should be first of
all blocked out in its generalities; that we should learn precisely what
formations were represented in the State, their order of superposition,
their mineral character and contents, their thickness and the geographical areas occupied by their outcrops.
To accomplish this work, our field was divided into four districts, consisting of the north-east, the south-east, the south-west and the northwest quarters of the State, all cornering at Columbus. The immediate
supervision of the work in the north-eastern section was assumed by myself; that of the south-eastern quarter by Prof. Andrews; of the southwestern by Prof. Orton; of the north-western by Mr. Hertzer and Mr.
Gilbert. To Prof. Andrews were assigned Messrs. Ballantine and Irving
as assistants; to Prof. Orton, Messrs. Newton and Whiting. Messrs.
Read, Sherwood, Hooker and Potter werb occupied in the northern half
of the State, and Mr. Prime devoted himself to the duty for which he
was especially qualified-the investigation of our mines, and manufactures based upon mineral staples.
Fortunately for the success of our efforts in this portion of our duty, an
excellent topographical map of Ohio had recently been made by my
friend, Prof. Walling, and published by H. S. Stebbins, of New York.
Of this map numerous copies obtained in the sheets were placed in the
hands of the members of the corps. To economize time, and secure the
benefit of a division of labor, the different formations were assigned to
different observers. The younger members were made each familiar with
a stratum or formation, and then, with map in hand, they followed it
wherever it led, carefully tracing its line of outcrop. They were also
instructed to make observations and take notes on all the subjects we
were required to investigate, with the injunction to so thoroughly perform their work along each line of observation that it might never be
necessary to go over the ground a second time. The scope of the observation made by our corps will be best comprehended from the following
schedule of instructions placed in the hands of all: