242 GEOLOGY OF EASTERN WISCONSIN. 



degrees, from a very slight impurity, to that which is more properly 

 denominated much. The depth of these deposits is also exceedingly 

 varying. In the investigations of the survey, an auger capable of 

 penetrating 12|- feet was used. In most of the peat deposits occupy- 

 ing open marshes, this was found sufficient to penetrate to the bottom. 

 In most of those arising from the sphagnum mosses in the forest 

 region, the depth was found to exceed that amount. In some cases 

 marshes were said to have a depth of two or even three times that 

 amount. The quantity of peat in eastern Wisconsin is to be reckoned 

 by millions of tons. 



Details of Borings. The first marsh tested occupies portions of sections 28, 29, 30 

 and 32, town of Whitewater (T. 4, R. 15 E). Ten borings were made along two hneB, 

 one across the marsh and one longitudinally. 



1. The first boring was on a springy elevation, near the center of section 32, from 

 which the hne stretched northward across the marsh. The peat at this point was very 

 much mixed with shells, travertine, and apparently some argillaceous material. Sandy 

 clay waa reached at a depth of 11 feet 4 inches. A ditch near by exposed a washed sur- 

 face of the upper portion from which were taken fresh water shells of the genera Sphaer- 

 ium Planorbis, Lunnsea, and Pupa, the smaller species of these genera being very 

 abundant, the larger, rare. This shows that the peat is of lacustrine origin, and that at 

 no distant day this has been a lake. 



2. At 50 rods from the first boring, we find about equal proportions of shell-marl and 

 peat. The following is the section: 



Soft, watery, dark reddish, marly peat 4 ft. 6 in. 



Thia layer of whitish marl 2 in. 



Peat as above 1 ft. 



Hard, well decomposed peat 4 ft. 



Bluish clay, Mod with pebbles at 9 ft. 8 in. 



3. The third boring gave the following section : 



Marly peat 4 ft. 



Hard, compact peat 5 ft. 6 in. 



Clay at 9 ft. 4 in. 



The bottom of a ditch near by contains calcareous sand, evidently washed from the peat. 



4. The fourth boring gave 8 ft. 8 m. of reddish, partially decomposed marly peat, con- 

 taining shells. Bottom blue clay as before. 



A section exposed by a ditch between borings 4 and 5 gave 2 ft. of peat, succeeded 

 by 4 in. of sheH-marl mingled with peat. 



5. The fifth boring showed 2 ft. of moderately decomposed marly peat as before, 3 ft. 

 somewhat more compact, with hard blue clay at 6 ft. 



The remaining borings were on a line from the S. E. qr. of the S. W. qr. of sec. 29, to 

 the N. W. comer of the S. W. qr. of sec. 29. 



6. The first two borings were made to ascertain the structure of a mound 6 feet high 

 and about 50 feet in diameter. The boring at the base gave 3 feet of muck-like peat, 

 with clay below; that in the top of the mound gave 7 feet 8 inches of peat, mingled with 

 much travertine, with clay and sand mingled at the bottom, which is about m feet 

 above the bottom of the bormg at the base, showing an acomnulation of sand and clay 

 beneath the mound, which undoubtedly owes its origin to a spring. 



