1871.] 81 [Niles. 



subject of special study. In November, 1870, he first called my at- 

 tention to them by quite a full account of what had been observed. 

 To me the facts were both new and interesting, and I have since 

 made visits to the locality, that I might personally observe and study 

 them. With the consent of Mr. Flynt and his foremen, I shall, in 

 the present paper, give some account of the facts they have nar- 

 rated to me, as well as of my own observations, in order that the 

 subject may be more fully elucidated. 1 



The quarry is located in the belt of gneiss, which lies east of 

 the red sandstone of the Connecticut Valley. From the city of 

 Springfield, Mass., the quarry lies east about 4° north, and at a dis- 

 tance of about twelve miles and a half in a direct line. In going 

 towards the quarry from Springfield, at a distance of about seven 

 miles and a quarter in a direct course and in the town of Wilbraham, 

 we come to the eastern edge of the red sandstone, and the base of 

 the first range of hills forming the eastern boundary of the Connecti- 

 cut Valley. These hills of metamorphic rock reach about six hun- 

 dred feet in height. Crossing the range to the eastward, we descend 

 into the valley in which the village of Monson is situated. The quarry 

 is located on a low foot-hill at the eastern base of this first range. It 

 extends from near the crest of the hill, over quite an area upon its 

 southern end and western side, and where the surface is only gently 

 inclined. 



The rock at the quarry is chiefly gneiss. It is of fine, even-grained 

 texture, quite free from impurities, and valuable for architectural 

 purposes. The strike is north 10° east, 2 and the dip is west 10° 

 north, at an angle of 80°. The rock is not divided by planes of 

 stratification, but a set of parallel joints, cutting transversely to 

 the stratification, divides it into regular beds, that at a distance, 

 might be mistaken for strata. These beds incline only about 10° 

 from a horizontal position, and are nearly parallel to the general sur- 

 face of the hill. They vary in thickness from a'few inches to several 

 feet. 



In quarrying, the beds are first broken at the lower or western 

 side of the quarry. The stone is then obtained by first drilling small 

 holes in rows, parallel to the strike of the stratification, and upon the 

 upper surface, of the beds. Into these holes wedges are driven, 



1 Since this paper was read, it has been so enlarged as to include the observations 

 made up to the time of publication. 

 ~ Magnetic. 



PROCEEDINGS B. 6. N. H. — VOL. XIV. 6 AUGUST, 1871. 



