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Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume V (1877-1881)

Swezey, G. D.
On some points in the geology of the region about Beloit,   pp. 194-204 ff. PDF (2.6 MB)


Page 198


198     WFisconsin Academy of Sciences, Arts, and Letters.
tion, just what we should expect; and so it is believed that this
well marlked seam is the same at Janesville, at the Second quarry
and at Carpenter's, and it is made the point of division between
the Lawer Blue and Upper Buff beds. The upper part of Carpen-
ter's quarry shows the Lower Fucoidal layers with their character.
istic conchoidal fracture and brown markings, the Birdseye and in
the very top the Upper Fucoidal. At Hess' quarry, a mile and
three-quarters farther south, and at IHanchett's, another mile be.
yond, as well as at Rockton, four miles farther, these same
layers are shown. Our next step in the ascending scale is made
by the Cherty quarry, four miles to the north, and here our ladder
breaks again and we must cross the state line and steal a few facts
from our Sucker neighbors to splice it with. We learn from the
Rockton quarry that the Cherty beds lie immediately above the
three feet of Upper Fucoidal layers, and, although the lower part of
the chert-bearing beds at Rockton are of a decidedly brecciated
structure, while at the Cherty quarry they are not yet, we must
conclude that they are the same, only laid down where the waves
broke more violently, as might not be unlikely eight miles away.
Moreover, the very top of I[ess' quarry, although badly weathered,
seems to be in this same horizon, and probably just about matches
with the bottom of the Cherty quarry. In the upper half of this
quarry and the two adjacent outcrops, we have the Upper Blue
beds, while in one of them a higher exposure, separated by thir-
teen feet unexposed, shows the Galena beds with their charac-
reristic receptaculites. The exact matching of these three quarries
s a hopeless task; but among the numerous shaly seams there
are two in each quarry that are well marked and about the same
distance apart, which are believed to be identical. If this is so,
the thickness of the Upper Blue layers is at least sixteen feet, and
above this there is seven and a half feet between the top of the
third quarry and the bottom of the upper exposure at the lime-
kiln. Between these limits of sixteen and twenty-three and a
half feet we may exercise our Yankee faculty of guessing; our
guess is twenty feet. At Smith's quarry we find this junction of
the Upper Blue with the Galena limestone which falls somewhat
between the limits above mentioned. Our estimate gives the


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