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)
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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