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at all, but deliver their water to the pervious alluvium of the valley, 

 and build their transported sediment into alluvial fans. These fans are 

 a prime characteristic of the larger valleys of the driftless ai'ea. 



In one instance tlie water-producing qualities of a valley of the 

 Knobstone region have been carefully investigated by the writer, in con- 

 nection with the investigations instituted with a view to obtaining the 

 best available water-supply for Indiana University. This is the case 

 of the valley of Griffey Creek at a point four miles due north of Bloom- 

 ington. The valley at this point is about 3,000 feet wide, and the drainage 

 area above the point where the tests were made is about seven square 

 miles. The valley receives its water from steep slopes, and is entirely 

 outside of the glaciated region. It contains no glacial drift of any 

 sort. At the point named, four holes, about e(iually spaced across the 

 valley, were drilled with an eight-inch soil augur through the alluvium to 

 bed rock. The two nearest the west ^ide of the valley reached a coarse 

 impure gravel at a depth of eight feet. The two toward the east side of 

 the valley pa.s.sed through eighteen feet of fine silt, and very fine dark 

 blue sand, and finally through two feet of coarse gravel to bed rock. All 

 of these bores reached bed rock at a depth of about twenty feet. 



At the second hole from the west side of the valley, a measurement 

 of the rate of flow of the ground-water was made in the following man- 

 ner: Four drive points were sunk into the gravel beds, so placed that 

 one well was up stream and three down stream. The three down- 

 stream wells were two feet from each other and each four feet from the 

 up-stream well. The middle down-stream well and the up-stream well 

 were as nearly as possible in the main axis of the valley. The up-stream 

 well was then dosed with fluorescein, and the interval that elapsed before 

 the reagent could be detected in the down-stream wells was noted. At 

 the end of six hours the fluorescein was first detected in the middle down- 

 stream well. It did not appear in the other two down-stream wells. It 

 Is believed that the fluorescein would not have diffused at a rate that 

 would introduce any appreciable error into this computation, and conse- 

 quently the rate of flow of the ground-water under this valley may be 

 taken as about two-thirds foot per hour, or sixteen feet per day. Near 

 this same spot a largo test well, five feet in dianH'ter, was sunk to be<l 

 rock. This well passed through eight feet of fine silt and twelve feet of 

 fairly clean gravel. Careful tests of this well made by pumping it out 



