CHAPTER III. 



LOCAL SECTIONS ON THE WISCONSIN AND BAKRABOO RIVERS. 



Wisconsin River. — As detailed descriptions have elsewhere been given of the 

 various beds composing the bluffs in the immediate vicinity of the mouth of the 

 Wisconsin River, I commence this part of my Report with an exposition of the 

 stratigraphical details four miles above the mouth. At this point the hills have 

 an elevation of four hundred feet, the Lower Magnesian Limestone, F. 2, is in 

 place near the water's edge, and two miles further up on the south side is a good 

 section. The different members, with their relative thickness, occur as follows : 



Feet. 



1. Base, concealed by vegetation, but probably occupied entirely by Mag- 



nesian Limestone, F. 2, . . . . . 160 



2. Lower Magnesian Limestone, exposed in a perpendicular cliff", the upper 



beds cherty, and containing Ophileta (?) and Buomphahts, . . 40 



3. Yellow quartzose sandstone, similar in texture and grain to the equiva- 



lent bed at the mouth of the St. Peter's, but not so white, . . 1'26 



4. Buff calcareous rock, partially exposed, .... 34 



Near the base of No. 3, the rock is composed of angular grains of quartz, loosely 

 cemented, and some layers are ripple-marked ; near its junction with No. 4, it is 

 made up of rounded grains, and some beds possess almost an oolitic structure. 

 No. 4 contains some organic remains, but not in a good state of preservation. 



Beyond the Ferry House, only ledges of Lower Magnesian Limestone can be 

 seen projecting at intervals on the slope. Loose slabs of sandstone are, however, 

 found near the water's edge. 



For two miles above the last section, the strata rise rapidly, so that the Lower 

 Sandstone, F. 1, already forms at this point eighty feet of the base of the hills, the 

 lower beds being thick, compact, and fine-grained ; the upper, coarser and thinner- 

 bedded. For about one hundred feet, there are intercalations of magnesian lime- 

 stone, with the sandstone, F. 1, /, the layers varying from an inch to a foot in 

 thickness, and divided by vertical cracks ; towards the top they assume an oolitic 



