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.

GEOLOGY OF MONTGOMERY COUNTY.
Prof. J. S. NEWBERRY, Chief Geologist:
SIR:-As Assistant in the Geological Survey of Ohio, I beg leave to
make the following report:
My work during 1869 was confined to the Third Geological District of
the State, viz., South-western Ohio, having for its boundaries the Scioto
River and the National Road.
The instructions that I received from you, bearing date May 7th, 1869,
required me to undertake for my first duty, " to trace the line of junction
of the Blue Limestone and Cliff Formations-that is, to mark out the
Blue Limestone area, and, at the same time, to collect materials for
resolving the Cliff into its component elements."
This work I entered upon June 1st, 1869, and continued to be engaged
in it, without interruption, until November 20th, 1869.
The report which I herewith transmit treats of the Geological formations that are found along this important line of junction, together with
their various economical products and their agricultural relations.
I take great pleasure in acknowledging that I have derived very valuable assistance in my work from the Geological Report of Dr. John
Locke, of the former Survey, upon this same portion of the State.
I desire also to acknowledge the very competent and faithful services
of Mr. Henry Newton and Mr. H. A. Whiting, volunteer assistants in my
district. I am also indebted to Mr. T. J. Browne for important aid in
mapping the isolated areas of the Cliff Limestone, in the southern part
of Greene county.
I have the honor to remain,
With great respect,'Very truly yours,
EDWARD ORTON.
YELLOW SPRINGS, OHIO,
March 9th, 1870.