QUARRIES IN KNOX COUNTY. 133 
except that the potash feldspar is a little more pinkish buff and the 
white soda-lime feldspar is of a slightly greenish tinge. The general 
tone of the color is " warmer. ,, The thin section shows rarely a 
little hornblende. 
The quarry is on the west side of a 100-foot high ridge. It 
measures about 500 feet square and has an average depth of 25 feet. 
No stripping or pumping is necessary. 
Rock structure: The sheets dip 10° W. in the front (western) 
part of the quarry, but gradually turn at the back or working face 
to 10° E. They range in thickness from 4 to 15 feet. About 'JO feet 
below the top of the quarry face is a bed of granite sand, IS inches 
thick, parallel to the sheets, already referred to on page 55. The 
principal joints strike N. 80° W. and dip 80° S., forming a 5-foot 
heading at the south end of quarry, and recurring but once or 
twice. The rift is vertical, trending N. 10° E. Owing to the struc- 
ture here, it is usual to blast by lewis holes along the grain (east- 
west) and then to split by plug drilling along the rift; in this Avay 
thick sheets can be split along the grain a distance of 200 feet. One 
block loosened measured 300 feet along the grain by 120 feet along 
the rift and was 15 feet thick. Dikes of aplite are rare. A knot 
from this quarry is described in detail on page 49. Sap measures up 
to C> inches in thickness along the sheet and joint surfaces. It is 
intense in color at the surfaces. 
The plant consists of 5 derricks, 2 hoisting engines, 2 steam drills, 
1 Ingersoll & Sargeant Duplex steam-driven air compressor (capac- 
ity, 525 cubic feet of air per minute), 1 channeler, 7 pneumatic plug 
drills, and 1 granite lathe, capable of carrying columns 70 by 7 
feet, made by Cheney & Spiller, of Boston. 
Transportation is effected by cartage of 700 feet to wharf, where 
the blocks are laden on schooners and taken either to the cutting 
sheds at the Sands quarry or directly to market. 
The product is used chiefly for bridges and buildings, and the 
waste is made into paving blocks. This quarry, in common with the 
Sands quarry, furnished the material for the new New York custom- 
house. It supplied also 8 columns, 51 J to 5-1 feet long by G feet in 
diameter, for the cathedral of St. John the Divine in New York. It 
was intended that they should each be of one piece, but as both the 
direction of the rift at the quarry and architectural principles re- 
quired that they be cut with their long axes at right angles to the 
rift, the strain in the great lathe came upon the weakest part of the 
stone. However, as the first stone put into the lathe broke with a 
long diagonal fracture, it became evident that the chief difficulty 
was that the stone had been subjected to too great a torsional strain 
by the application of rotary power from one end only. It therefore 
