PREFACE. WAY 
Survey, it would probably not be difficult to prove that the increase in the value of 
property in a single township consequent upon the development of its coal mines—a 
development prompted and directed by the Geological Survey—has exceeded ten-fold 
its entire cost. Yet the benefits which will follow an accurate knowledge of the 
geological structure and mineral resources of the State have only just begun to be 
felt, and they will continue to operate for centuries. 
As compared with similar surveys made in other States, it is believed that it will 
be difficult to point to any one which has been brought to a completion within as 
short a time, and with so small an expenditure of money, and yet in which as much 
and as good work has been done. 
That the geology of the State is exhausted, that all desirable facts are gathered in 
reference to our useful minerals, that no errors have been committed—none of these 
things are claimed ; but it is asserted that an honest and energetic use was made of 
the time and money expended on the Survey; and that its fruits will be worth much 
more than their cost to the people of Ohio. An exhaustive survey of the State, with 
tts area of 39,964 square miles, its varied geology, its innumerable fossils, and its great 
and diversified mineral wealth, would require many years of time, and would cost 
perhaps a million of dollars. The present Survey was originally limited in time to 
three years, and though it was said by those who initiated it that it could not and 
should not be finished in less than ten years, and it was continued by special enact- 
ments more than a year and a half beyond the term first prescribed, the financial 
condition of the country at the close of 1873 prompted the Legislature to instruct the 
Geological Corps to bring the work to an end. 
In these circumstances it has been impossible for the Geological Corps to accom- 
plish all they had hoped to do in the commencement of the Survey; and if it should 
be found that the reports of the Survey do not supply all the information desired on the 
subjects of which they treat, it should be remembered that the work has been under 
such restrictions of time and money that greater perfection was not attainable. In 
view of all the embarrassments and uncertainties under which the Survey has been 
carried on, it may be a matter of congratulation to all who have been interested in 
its progress that it has attained the degree of symmetry and completeness it now 
presents, and that in the scale of expenditure and measure of detail adopted it has 
been brought so nearly to a successful close. 
