1871.] 83 [Nilea 



Spontaneous fractures, similar to the one described above, hare 

 been visible at the quarry whenever I have visited it. Sometimes 

 they are quite large. I measured one, July 7th, which was full four 

 inches wide. 



Another series of phenomena is exhibited at the quarry, in the 

 spontaneous elevation of the beds and the formation of miniature 

 anticlinals. These elevations are common, and affect beds differing 

 in thickness. In April I observed two anticlinals which had been 

 recently formed. In one instance, a bed one foot eight inches thick 

 had been elevated one inch and a half. The curvature of the upper 

 surface of this bed was most distinctly visible. From the crest of 

 this anticlinal to the base of the northern slope, the distance was 

 twenty-three feet. The base of the southern slope could not be de- 

 termined on account of the debris which had accumulated there. At 

 one end of the crest there was a crack three-sixteenths of an inch 

 wide, trending with the fold nearly east and west, but at the other 

 end no fracture could be seen. In the other instance the bed was 

 three inches thick, and at the centre had been elevated one inch. A 

 fracture extended the entire length of the crest, which trended nearly 

 east and west, as in the pi^eceding instance. 



On the afternoon of July 7th, a little anticlinal was formed while I 

 was at the quarry. The bed was only two inches and three-fourths in 

 thickness. The span of the arch from north to south was. five feet 

 five inches and a half. The length of the crest was five feet and a 

 half, and a fracture extended the entire length of it. During the ' 

 afternoon, the portion of the bed forming the crest was elevated three 

 inches and a quarter. The situation showed that the force which 

 caused the elevation, was not an artificial one used in working the 

 quarry. 



According to the testimony of the persons occupied at the quarry, 

 explosions sometimes attend the fracturing and elevation of the beds. 

 Mr. A. T. Wing, superintendent at the yard, says that cracking 

 sounds are very frequently heard, especially after the work of the 

 day, and the noise attending it has ceased. Though these sounds are 

 more frequent in warm weather, yet they are heard in winter. 

 These explosions sometimes throw dust into the air, and he has seen 

 stones, weighing a few pounds, thrown several feet high by them. 

 The sound of these explosions is sometimes as loud as the blasting 

 of rock, and in a few instances it has been even louder. At one 

 time, after the workmen had left the quarry, so loud a report was 



