ewer nemae hea il t 
a 
Geological Survey of the State of Ohio. 353 
limestone imposed upon it. As an article of traffic, Dr. Hildreth 
says : 
“The importance of this article in a commercial and domestic point of 
view, may in some measure be estimated, when it is stated by intelligent 
persons, who have been long engaged in the manufacture of mill-stones, 
that the annual amount of the manufactured article is not less than 
$20,000; and that it may be safely calculated at this sum, for twenty 
years past. When to this, is added the money saved to mill-owners, from 
the use of the native instead of the foreign buhr-stone, that amount will be 
nearly doubled. It came into use about the year 1807. The early man- 
ufactured mill-stones were made of a single piece; but these often proving 
to be of unequal density, and not making good flour, were abandoned, 
and staves constructed of separate blocks, cemented with plaster, and 
confined togther with iron bands. Where these blocks are selected with 
care, by an experienced workman, the flour is said to be equal in quality 
to that made by the French stones. 
“From the year 1814 to 1820, the price of a pair of four and a half feet 
stones was $350, and a pair of seven feet, sold for $500; while the for- 
eign article sold for a still higher sum. The four feet stones now sell for 
$150. In the townships of Richland, Elk and Clinton, a large number 
of the inhabitants are engaged in the dressing of blocks, and in the con- 
struction of mill-stones. The buhr-rock is a mine of wealth to the inhab- 
itants, and has contributed largely to the prosperity and independence of 
this whole region of country. The manufacture of mill-stones is not con- 
fined to the waters of Raccoon, but is also carried on to considerable ex- 
tent in Hopewell township, Melicniokn county. The quantity is appa- 
rently inexhaustible, and new quarries will be opened, at points where it 
is not at present looked for, and ehh of a more even and compact 
texture than that now obtained. Few or no quarries have been yet worked 
by drifting under the sides of the hills, eat the rock is generally procured 
by what is technically called “ stripping,” or excavating the superincum- 
bent earth, near the top of some ridge or hill, where it is easy of ac- 
cess,” p. 33. 
His remarks on the salt springs are copious and interesting ; but 
Wwe must pass them without comment. In taking leave of this 
report, we express our pleasure in its perusal, and our conviction 
that it will enhance the well-founded reputation of Doctor Hil- 
, a8 a scientific observer. 
The report of Dr. Kirtland, from the nature of his department, 
does not admit of much detail. He has briefly and succinctly 
set forth some of the advantages which may be expected to arise 
Vor. XXXIV.—No. 2. 
