514 LOCAL SECTIONS 



Feet. 



7. Slope, where rocks concealed, ...... 40 



8. Hard, brown sandstone, in thin beds, somewhat calcareous and magnesian, 8 



9. Slope, with occasional ledges of coarse-grained sandstone protruding in 



massive beds, ....... 72 



10. Lower Magnesian Limestone, F. 2, . . . . 5 



Total, . . .303 



Bed No. 6 splits with a conchoidal fracture, and has cavities partially filled 

 either with concretions of iron or blende. It has the lithological character of the 

 Trilobite-bed on Lake St. Croix, and contains the same Lingulas. 



From the above section it appears that on this part of the Wisconsin thick- 

 bedded brown and white sandstones, containing but a few fossils, take the place of 

 the coarse Lingula and Obolus grit, F. 1, c, of the Mississippi sections ; and the 

 same fact will appear from some of the succeeding sections. 



For about fourteen or fifteen miles above Helena, no good sections present them- 

 selves. 



On Section 20, Township 9 north, Range 6 east, of the 4th Principal Meridian, 

 the following section was measured. 



Feet. 



1. Soft, white sandstone, passing upwards into coarse, brown gritstone, . 60 



2. Coarse sandstone, composed of angular grains of quartz, . . 4 



3. Brown, compact, calcareo-magnesian rock, with alternating beds of brown 



sandstone, ........ 35 



4. Brown sandstone, rather fine-grained, ..... 5 



5. White and brown sandstone, interstratified with siliceo-calcareo-niagne- 



sian rock, like the beds of No. 3, but more arenaceous ; some green- 

 sand disseminated, ....... 87 



6. Partial exposures of sandstone, and thin layers of magnesian limestone, 26 



7. Slope, covered with vegetation and soil, and masses of brown, ferruginous 



sandstone, ........ 48 



Total, . . . 265 



The sandstone at the bottom of bed No. 1 is exceedingly white, being composed 

 of limpid grains of quartz, loosely cemented, so that with a slight blow it crumbles 

 easily to a white sand ; the upper beds of No. 1 resemble the coarse Lingula grit 

 of Lawrence Creek. 



Bed No. 2 contains small, rounded, and angular concretions of ferruginous sand, 

 and some particles of silicate of iron and ferruginous stains. 



Bed No. 3 probably corresponds to the brown Orthis rock, No. 3 of the section at 

 La Grange Mountain. Bed No. 6 has the lithological character of bed No. 4 of 

 the La Grange Mountain section. 



Two miles below Saukville, the hills near the river seem to be composed mostly 

 of drift materials. 



Nearly opposite Saukville, the hills are a little over two hundred feet high, and 

 present the following section : 



