198 Wisconsin Academy of Sciences, Arts, and Letters. 



tion, just what we should expact ; and so it is believed that this 

 well marked seam is the same at Janesville, at the Second quarry 

 and at Carpenter's, and it is made the point of division between 

 the Liwer 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 Hanchett's, another mile be- 

 yond, as well as at Eockton, four miles farther, these same 

 layers are shown. Oar next step in the ascending scale is made 

 by the C her ty 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 Cberty 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 Hess' 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- 

 teristic receptacidites. The exact matching of these three quarries 

 is 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 6nd this junction of 

 the Upper Blue with the Galena limestone which falls somewhat 

 between the limits above mentioned. Our estimate gives the 



