Geology and Natural History. 433 



of fracture the rock is broken into pieces varying in size from 

 a few square inches to several square yards. The fault dis- 

 appears where the crack passes out from under the mill ; and 

 here the splintering is confined to a depth of two or three 

 inches and a width of four or five. The chips vary in size 

 from half an inch to two or three inches square, and many 

 of them are scarcely thicker than a sheet of paper. Beyond this 

 the ridge, the fault and the crushed rock disappear and there is 

 nothing to indicate a disturbance, except a clean fracture, which 

 ends in the quarry. 



There have been observed, in this region, two or three other cases 

 of fracture which will throw light in the search for the cause of the 

 fracture at the Combined Locks. Between the last two locks in 

 the government canal at Kaukauna, about sixteen inches of the 

 upper rock layers had been removed, leaving a layer three and a 

 half inches thick at the surface in the bottom of the canal. Be- 

 fore navigation opened last spring the canal bed was examined, 

 and this upper layer was found fractured and raised into a ridge 

 for a distance of about twenty-five feet along a line of drill-holes 

 that had passed through it. It was proved beyond a doubt by 

 the conditions observed on the spot and by the testimony of men 

 who helped remove the rock in the canal, that the ridge was not 

 formed until at least one season after the canal had been finished 

 and in use. The one layer was raised sixteen inches, leaving a 

 hollow underneath. The fracture passed along the line of the 

 drill-holes, and formed the axis of the ridge. Its direction was 

 N. 20° E. parallel with that of the canal and the river. 



Only a few hundred feet away from the canal another break in 

 the rock occurred in June, 1889. At this point the high clay 

 bluff bends away from the river, leaving a large flat, but little 

 above the river level, and with the rock almost bare of soil. On 

 this flat, at the south end of private claim 33, there Was a quarry 

 four and a half feet deep. A six-inch layer of limestone formed 

 the floor of the quarry, at one end of which a hole seventeen 

 inches deep had been blasted as a start for the next "level." 

 The water was pumped out of the quarry in June ; and after four 

 or five days of warm weather, while some men were working just 

 behind a knoll, they heard a noise which they described as being- 

 like that of exploding dynamite. The layer forming the floor of 

 the quarry was fractured ; the crack started from the hole at one 

 end and ran down the middle of the quarry for some distance, 

 and then bifurcated, the branches running to the two corners at 

 the south end. The rock was lifted into a ridge sixteen inches 

 high, and in some places split into thin plates. The fracture ran 

 at right angles to the river and the high clay bank. 



A paper mill has recently been built at Kimberly, three miles 

 down the river from Appleton, and three miles up the river from 

 the Combined Locks. A large quarry four feet deep was opened 

 in the river bed below the o-overnment dam. While Mr. Charles 

 Riggs, the contractor, and the men at work in the quarry were 



