HYDROLOGY. 167 



At 680 feet, fine grained white quartzose sand; slight effervescence. 



At 640 feet, fine grained quartzose sand, with slightly reddish clay-like calcareous 

 material. 



At 710 feet, fine grained, light colored, quartzose sand; slight effervescence. 



At 758 feet, rather coarse, white and slightly greenish quartzose sand, with a little 

 clayey material; no effervescence. 



At 940 feet, coarse white quartzose sand. 



At 975 feet, similar to above, but coarser. 



At 1022 feet, very coarse, transparent quartz sand, some of the grains one-sixth of an 

 <nch in diameter. 



Bottom, 1033 feet. 



STJMMAKY. 



Drift 360 feet. 



Red and green rock, probably Mendota horizon 10 



Fine grained, slightly calcareous sandstone 155 



Calcareous shale 80 



Fine grained, very slightly calcareous sandstone 163 



Coarse non-calcareous sandstone 275 



Total 1033 " 



Drift, 350 feet. Postdam, 683 feet. 



Probably 40 to 50 feet of the upper portion of the Potsdam has 

 been removed, making the thickness about 725 feet, with the bottom 

 not reached. 



In the upper portion of the Potsdam horizon, a vein was struck 

 which gave a permanent rise in the tube of 48 feet above the water 

 level in the open well, without the aid of a seed-bag or other appara- 

 tus for preventing lateral leakage. This corresponds, according to 

 aneroid measurement, to 147 feet above Lake Michigan, or 7 feet 

 above the depot at Janes ville. 



The unusual thickness of the drift is probably due to an old pre- 

 glacial caflon of Rock river, now filled, as the full series of formations, 

 up to the Trenton limestone, occurs on the opposite side of the river, 

 and also at a short distance to the east. The circumstances that ne- 

 cessitated the selection of the fair grounds for this test well are to be 

 regretted, since at the locality for which my estimate was given, the 

 exceptional difficulties with the drift would not have been encoun- 

 tered, and a satisfactory flow would undoubtedly have been obtained. 

 Nevertheless, through the enterprise and ingenuity of the parties hav- 

 ing the matter in hand, a success scarcely less satisfactory has been 

 attained. Advantage has been taken of the rise of 48 feet in the tube 

 above that in the well, to raise a portion of the generous flow to the 

 surface by hydraulic appliances. 



Possibilities of obtaining wells at other points. Reference has 

 been had to this important practical question in the foregoing des- 



