206 GEOLOGY OF ILLINOIS. 



it is tapped. This abundant supply can be reached anywhere in the northern 

 part of the county at about four hundred feet, and in the southern part, at 

 probably nowhere more than six hundred feet, and in part of it, much less 

 than that. Any one boring for this in the prairie, where drainage cannot 

 readily be had in every direction, should be careful to so locate his well as to 

 avoid the fate of certain residents of Iroquois county, who have allowed the 

 surplus water of their wells to saturate the soil of their orchards, and so drown 

 their trees. 



" Gras " wells in the boulder clay are known at two localities. Near the 

 northeast corner of section 3, township 32 north, range 6 east, Mr. Whitton's 

 well, at twenty feet, gave off so much carbonic acid as to prevent farther exca- 

 vations. Probably this flowed from some ancient soil, like the muck beds en- 

 countered in Livingston, Champaign and McLean counties. On section 35, 

 township 34 north, range 6 east, Mr. Cassel's well, at forty-seven feet, gave off 

 light carburetted hydrogen with so much noise as to be heard at a considerable 

 distance, and in such quantity as to blaze " as high as the house," for some 

 fifteen minutes after being approached with a lighted candle. The gas still 

 flows freely, though it is several years since the well was dug, and a wagon- 

 load of gravel has been thrown in to act as a filter for the water, which was at 

 first filled with quicksand, brought up by the ebullition of the gas. Similar 

 phenomena have been observed in wells recently dug, about a half a mile far- 

 ther south. Near the south line of section 22, in the same township, on land 

 of Mr. Samuel Hodge, is a large spring which constantly gives off bubbles of 

 this gas. Springs of this character have been found by Capt. H. C. Freeman, 

 to accompany the outcrop of the lower seam of coal, in the adjoining part of 

 LaSalle county, and I am inclined to accept them as partially indicating the 

 coal outline here, where the depth of the Drift prevents actual observation of 

 its position. 



