LOCAL SECTIONS ON THE WISCONSIN RIVER. 



511 



structure, as has frequently been observed in the corresponding beds in the Missis- 

 sippi sections. No rocks are exposed here in the hills above these beds of passage 

 between F. 1 and F. 2. 



Between the Upper and Lower Ferry, the hills on the south have a greater eleva- 

 tion than those on the north side of the river. From the wooded slopes of the 

 former only occasional outcrops of rocks are visible. 



At the second ferry, the bluffs recede from the river, and are succeeded by low 

 bottom-lands, elevated about three feet above the water. These continue within 

 three miles of the confluence of the Kickapoo. On the south side, the hills run 

 parallel with the Wisconsin River, with a narrow strip of bottom-land between, 

 having an elevation, where they were measured, of three hundred and fifty feet- 

 Near the summit, the cherty beds of F. 2 are occasionally exposed, in vertical walls, 

 but the underlying beds are concealed by vegetation and soil. 



On Section 16, of Township 7 north, Range 4 west, the strata occur in the fol- 

 lowing order : 



Feet. 



1. Thick-bcddcd brown and yellow sandstone, .... 103 



2. Alternations of sandstone and magnesian limestone ; oolitic near the top, 35 



3. Heavy-bedded magnesian limestone, ..... 172 



On the summit of the ridge, are loose masses of the upper sandstone, F. 2, c, but 

 no strata are visible in place. 



A mile further, low ledges of horizontal beds of sandstone alternating with mag- 

 nesian limestone are seen on the north bank of the river. The layers are from two 

 to six inches in thickness, and are traversed by vertical fissures. This exposure 

 extends up the river for nearly a mile, varying in height from six to fifteen feet. 



Some of the layers here consist of a siliceo-calcareo-magnesian rock, with green 

 particles of silicate of iron disseminated, and contain casts of OrtJiis, and one of the 

 species of Dikelocephalus found in the Lower Sandstone series of the Upper Missis- 

 sippi ; one bed seems to corresj)ond to the brown Orthis rock in the section at La 

 Grange Mountain. 



A mile further up the Wisconsin, green and yellow layers of Lower Sandstone, 

 F. 1, d, appear, having much the same lithological character and composition as on 

 the St. Croix and Mississippi. In the upper thinly laminated layers, fifteen feet 

 above the river, Lingulas occur, associated with a Trilobite, which appears to be the 

 same as one of the species afforded by the third Trilobite bed of the Mountain Island 

 section. The strata rise up stream, so that in a few hundred yards they attain an 

 elevation of thirty feet. 



The upland on this part of the Wisconsin is mostly wooded near the river, and 

 the soil good. 



About six miles above the last section, the bluffs were found to be three hundred 

 and sixty feet high. The base has a talus of loose masses of brown, coarse-grained 

 sandstone, interspersed with the soil. Some of these have siliceous concretions dis- 

 seminated, apparently the remains of decomposed fossils ; some specimens show the 

 angular structure of the body-plates of Crinoidea. One hundred and fifty-seven 



