The granite (specimen 38, a) is a biotite granite of medium t( light-gray shade and coarse, even-grained texture, the feldspars measuring up to 0.8 inches in length. It consists, in descending order of abundance, of potash feldspar (microcline and orthoclase), smoky quartz, soda-lime feldspar (oligoclase), and black mica (biotite), with accessory magnetite. The feldspars are milky white with a slight bluish tinge. The contrasts between the feldspar, quartz, and biotite are marked, more so than in the White quarry stone, because the feldspar is whiter, the quartz more smoky, and the biotite a trifle coarser. The following chemical analysis of this granite, made in 1896 by Ricketts and Banks, of New York, is inserted here merely for reference:
Analysis of granite from Chase granite quarry, near Bluehill, Me.
The same firm also made a test of this granite (test No. 16606, 1899) which showed that it has an ultimate compressive strength of 23,400 pounds per square inch.
The quarry, opened in 1872, consists of several openings on the top and eastern slope of a hill rising 220 feet above the sea in a distance of three-fourths mile. Drainage is effected by occasional use of siphon and pump.
Rock structure: The sheets are up to 8 feet thick and either lie horizontal or dip at a low angle. Vertical joints strike N. 50° W. and N. 40° E. The rift is vertical, with a north strike. There are some small dikes of aplite and dark-gray knots. Sap occurs in the upper sheets to a thickness of several inches. In one of the openings the stone has occasional light rust spots half an inch in diameter, which are due to the oxidation of some ferruginous mineral in very minute particles.
The plant consists of 9 derricks and 5 hoisting engines, 1 cable engine, 1 locomotive crane. 1 compressor. 4 steam drills, 3 pneumatic plug drills, 2 surfaeers, and 2 pumps.
Transportation is effected by a cable road 1,400 feet long from the main quarry to the cutting shed and by locomotive and track. 650 feet more, from shed to dock.
The product is used for buildings. Specimen buildings made of this granite are the New York Stock Exchange, Lying-in Hospital, Manhattan Trust Building, and Grand Union Hotel, Forty-second street, New York, the General Thomas monument, and the trimmings to the Bureau of Engraving and Printing. Washington, D. C.; the League Island dry dock, and the post-office at Harrisburg, Pa. Paving blocks are a by-product.
The Chase Quarries (monumental granite) are in the town of Bluehill. About 350 feet east of the upper opening of the Chase quarries is an area not less than 200 feet square, of a medium bluish-gray fine-textured, porphyritic biotite-muscovite granite (specimen 39, a). The particles range in general size from 0.07 to 1.1 mm. in diameter, averaging about 0.37 mm. The isolated feldspars measure up to onefourth inch across. The minerals, arranged in descending order of abundance, are potash feldspar (orthoclase and microcline), smoky quartz, soda-lime feldspar (oligoclase), black mica (biotite), and white mica (muscovite), with accessory magnetite. The feldspars are bluish gray. They have considerable intergrown quartz and the rock is generally harder than the adjacent granite, which it probably traverses as a large dike. It has been quarried occasionally by the company for local......