916 GEOLOGY OF OHIO. 
gave a practical guarantee of the validity of the claims that were made 
for it. 
From this time forward, our knowledge of its geology was rapidly 
enlarged. Stimulated by a desire to secure as much as possible of the 
great mineral wealth of the Valley, companies and individuals vied 
with each other in acquiring, in all available ways, a knowledge of its 
real resources. Geological examinations made for these companies by 
Whittlesey, Andrews and Read, and published as private reports, 
extended our acquaintance with the field, while many local geologists 
and explorers worked up with care and skill the sections of their own 
_immediate neighborhoods. At a somewhat later date, May, 1874, a 
report upon the field was prepared for eastern capitalists, by Dr. T. 
Sterry Hunt, of Montreal, Canada, which embodied the general facts 
of the geology as then understood, together with a number of valuable, 
original analyses of the minerals of the Valley. 
In 1878, Volume III, Geology of Ohio, was issued. It contained 
a somewhat extended report, by M. C. Read, Esq., on the Hocking 
Valley Coal Field, a supplemental report, by Professor EK. B. Andrews, 
on Perry county and portions of Hocking and Athens counties, or in 
other words, upon the Hocking Valley field, and also a supplemental 
report on the Hanging Rock District, in which the geological connec- 
tions between the Hocking Valley and the Hanging Rock district were 
discussed at some length. 
In 1881, Dr. Hunt published a second and much more complete 
review of the “ Mineral Resources of the Hocking Valley.” In it, he 
incorporated a great number of facts that had been brought out and 
established in the various reports already named, and he added many 
observations, measurements and analyses of his own, making the report 
on the whole a more complete account of the Hocking Valley than any 
that had previously appeared, but it would require more or less qualifica- 
tion in order to match with the facts as at present found. 
The progress of our knowledge has shown errors of observation 
and interpretation in all of these statements, and there are still differ- 
ences of view as to many questions pertaining to the geology of the 
district, but while each year adds tou our knowledge facts which could 
be gained only by the practical development of the field, it also gives 
increased assurance to our interpretations of the general order, and 
although there is still much to be learned, there is already, in our pos- 
