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.

4
to be painfully worked out by a careful examination of the rare exposures of their lines of contact. It was not easy nor even possible, in all
instances, to identify any of the formations by their lithological characters alone, for these are proverbially unreliable, and they are often found
to change completely in going from county to county. It is now well
understood, not only that fossils are safe and convenient guides in studying the relations and distribution of fossiliferous rocks, but that their
assistance is indispensable, and that no conclusions can be regarded as
accurate'and trustworthy unless confirmed by their evidence. The wellread palaeontologist finds in every characteristic fossil an infallible record
of the age of the rock that contains it, so that, when he can read the
language, the fossiliferous rocks are all ticketed to his hand. Nothing
can better illustrate the truth of these statements than the laborious and.
painful efforts of our pioneer geologists to determine, without palseontological data, the age and relations of our formations. After spending a
summer in the study of the group of limestones which underlie the western part of the State, Dr. Riddell, with considerable hesitation and diffidence, announces the opinion that the blue limestone of Cincinnati underlies and is older than the, buff limestone of Columbus. Even, two
years afterward, when the Geological Board, subsequently created, had
devoted two seasons of field work to the study of our geology, the exact
geological ages of these formations were still undecided.
Much valuable information was, however, contained in the reports of
the special committee, especially in that of Dr. Hildreth, where the first
glimpse is given to the public of the structure and richness of the southern iron district-lying between.Marietta and Portsmouth-where the
Coal Mleasure ores exhibit a development equalled in no other part of
our country, and where the iron industry of Ohio has, till lately, been
mainly centered.
In obedience to their instructions, the committee submitted a plan for
a general geological survey of the State, with an estimate of the necessary expenditure. The. Legislature of 1836-37 at once acted on the recommendation of the committee, and passed a bill on the 27th of March,
1837, providing for a geological survey, appointing a corps of geologists,
and voting an appropriation of $12,000 for the prosecution of the work
during one year.
The board then organized consisted of the following members:
W. W. MATHER, State Geologist.
DR. i. P. HILDRETH, 1
DR. JOHN LOCKE, I
PROF. J. P. KIRTLAND, sistat
J. W. OSTER, Assistants.
CHARLES WHITLESEY,
C. BRIGGS, JR.