QUARTZYTES AND SANDSTONES. 55 



1. Earth 1 to 2 feet. 



2. Thin, slaty layers alternating with beds of 



standstone 10 feet. 



3. Blue sandstone _ 10 feet. 



4. Slate (as pierced in well hole) 3 feet. 



In the upper ten feet there are three beds of sandstone, 2 J feet, 2 

 feet and 1 foot thick, respectively. The dip of the strata is less than 

 2° and is to the south-east. There are two well-marked systems of 

 joints ; one runs south 32° west, and dips 88° to north-west ; the other 

 runs south £9° east and dips 85° to 88° to south-west. These joints 

 divide the rock into rectangular and step-like masses, and are at con- 

 venient distances for working. The stone splits readily and true, and 

 is easily wrought into blocks for common wall work. Very little 

 powder is used, as the masses are broken off by bars and split by 

 sledging. There are no "sap faces" on the stone, and very little 

 calcite or pyrite. The stone is fine-grained. It is in the horizon of 

 the Hudson River slate and sandstone. And the bottom rock is 

 black slate, containing scattering sandstone pebbles and mud cracks. 

 No fossil organisms are found in any of the quarry beds. The drain- 

 age is natural, nearly to the floor of the quarry ; a Worthington pump 

 raises the water from the bottom to the level of the outflow to the 

 canal. A rock breaker at the side of the railroad track uses the spalls 

 and waste for road and street material. The stone is carted in wagons 

 to the railroad side track (within a quarter of a mile of the quarry), 

 or is loaded on canal boats at the side of the quarry. Albany, Cohoes, 

 and Troy are the chief markets. The stone is known in the market 

 as " Schenectady blue stone." The working season continues from 

 March to December. This quarry was opened in 1862. 



Levi Benedict's quarry is north of Aqueduct station an eighth of 

 a mile, and has the canal on its west side. The opening is about 60 

 yards long and 30 feet deep. The strata dip southward at an angle 

 of less than 5°. One main joint has a course of south 42° west. 

 Another of south 55° west ; and their planes dip 85° to north-west. 

 There is a third system whose direction is in general south-east, and 

 whose plane dips 85° to south-west, but it is not so well defined as 

 the others. The vertical succession of the strata is : 



1. Slate, brownish colored __ _ 10 feet. 



2. Slate and blue sandstone 9 feet. 



3. Blue sandstone 2 feet. 



