FRANKLIN COUNTY. 609 
First comes an eleven-inch course, some portions of which are blue in 
color, though the prevailing color isdrab. It is raised in larger blocks 
than any other course in the quarry. Two hundred square feet are easily 
obtained in a single block. It is known in the quarry, on this account, 
as the “big stone.” For platforms and other like uses, it is especially val- 
uable. 
The “ big stone” is followed by a seven-inch course, which sometimes 
yields cutting stone, but not regularly. This is followed by an eight-inch 
course, quite blue in color, that is, on the whole, durability, size, color, 
freedom from flint being considered, the most valuable course of the 
quarry. It is covered by a six-inch course that serves a good purpose as 
a curb-stone. This is followed in turn by the lower and upper “ hackle- 
tooth” courses, the former a six-inch course, and the latter an eight-inch 
course. These beds get their name from a sort of suture-like interlocking 
of their apposed faces. They are quite persistent throughout the district 
in which quarries are wrought, and serve as guides to the identification 
of the several sections. The lower course is most valued for cutting, 
chiefly because of the absence of flint from its substance. . 
Next in order comes a nineteen-inch course that cannot be raised in 
blocks large enough to make ita cutting stone. It goes in with the sec- 
tion that lies above it, for all heavy work for which the quarries have to 
provide. The section which we have now reached is called the “rough 
rock.” {tis put down in the scale as eight feet in thickness, but it is 
oftener four and one-half feet than eight feet. The rough rock is covered 
by one of the most persistent layers of the quarries. It is called by the 
quarrymen the “sheep-skin” course. It is four to eight inches in thick- 
ness; is raised in good sized blocks, and is largely wrought asa cutting 
stone. The steps of the State House are, to a large extent, derived from 
this layer. It is crowded with fossils, and these are brought out very 
distinctly by the wear of the stone. A well-known univalve shell, the 
Euomphalus De Cewi, Billings, belongsin this horizon, andis very often seen 
on the slabs that belong to this course. Cyathophylloid corals also crowd 
the surface frequently. 
Another series of building stones—in courses eight inches thick or 
less, making an aggregate of two and one-half feet—overlies the sheep- 
skin course, and this in turn covered by what is called the “smooth rock,” 
which includes about four feet in thickness. There are two flint courses 
in this interval that can be followed through the whole belt of quarries. 
They are easily separated from the rock in which they are bedded. The 
latter breaks very easily, and yields the best lime of the formation. It 
averages over ninety per cent. of carbonate of lime, and frequently rises ~ 
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