FRANKLIN COUNTY. 605 
Huron shale, occurs on the same side of the river, and but a little ways 
back, in various exposures, for eight miles to the southward.. The actual 
thickness of the sections found here is about seventy-five feet. 
A section found in this neighborhood, at Corbin’s Mills and on the 
adjacent land of Joseph Ferris, can be taken as a fair representative of 
the series here. It isshown in the annexed wood cut. Beginning at the 
water’s edge, a heavy course of cutting stone is first seen. Its thickness 
sometimes rises to two and one-half feet. This is overlain by eight feet 
of buff colored magnesian limestone, which lies in quite heavy but rather 
uneven beds. ‘These courses have a maximum thickness of three and 
one-half feet, and an average thickness of two and one-half feet. They 
are raised in blocks sufficiently large to make them valuable as a cutting 
stone. They are easily wrought, especially when first qua ried, and on 
this account have acquired the local names of “‘freestone” and “sand- 
stone.” 
These courses are followed by five feet of thinner bedded rock, the 
thickness of the layers ranging between four and eight inches. Two of 
these layers, one near the bottom and the other near the top of the sec- 
tion, hold flint concretions. These occur in irregular nodules, chalk 
white on the outside, and often of the same color throughout their sub- 
stance. They are very rich in the fossils of the formation, and these are 
here found in a remarkable state of preservation. Univalve shells of the 
genera Murchisonia, Loxonema, Pleurotomaria are especially abundant and 
perfect. Very fine casts of the brachiopod Meristella nasuta, Conrad, occur 
here also. Several of the type fossils of the formation were described 
from specimens found in the flint of this geological horizon. 
The flinty layers in the section are overlain by nineteen feet of light 
colored beds, commonly called “ white limestone.” These beds are crowded 
with fossils, of which brachiopod shells are the most numerous. The beds 
are thin, seldom exceeding six inches, and not veryeven. They furnish 
at the best “building stone” as distinguished from “cutting stone,” but 
the most valuable application that can be made of them is in lime burn- 
ing. They yield a very strong and very white lime. 
The nineteen feet shown in the quarry above the mill, together with 
the lower portion of the next division marked in the cut, constitute the 
Delhi beds of Prof. Winchell. *This next division, eleven feet in thick- 
ness, is not homogeneous, as has been already intimated. It is not clearly 
shown at this point, but the uppermost five or six feet are made up of 
shaly layers, not adapted either for building stone or lime burning. Their 
upper boundary is made distinct by a remarkable layer called the bone 
bed, which will be described in detail on a subsequent page. 
*See Keport on Delaware county, Vol. II Geology, page 297. 
