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NEW YORK STATE MUSEUM 



finally hardpan. There is a stripping of fine sand, which varies 

 from 10 to 20 feet in thickness. Some portions of this sand are 

 found to make a better brick when mixed with the clay than 

 others. The clay is mined in benches, and narrow tracks are 

 laid along the working face. Side dump cars are used to haul 

 the clay, being run in trains of three, drawn by four mules. 

 The tracks are laid around the ring pits, so that the clay may be 

 easily discharged into them. 



Below are given two partial analyses of clay from this bank : 



Crugers, Montrose and Verplank, Westchester Co: — These three 

 localities lie so connected and their clay banks are so similar that 

 they are best described together. The clay is extremely vari- 

 able in depth, due to the great irregularity of the face of the 

 underlying rocks ; it is both blue and yellow. ~No special method 

 is used in mining the clay, it being dug at any convenient spot 

 till the underlying rock is reached and then the bank is attacked 

 at another point. At Montrose and Crugers the clay is over- 

 lain in places by a moderately fine sand and gravel, crossbedded 

 in places. The clay varies from six to 50 feet in thickness. 

 It extends in places to an altitude of 90 feet, as at McConnell and 

 O'Brien's bank, while at others as McGuire's bank it only reaches 

 a height of six feet above mean tide. At this latter locality the 

 clay is overlain by 10 feet of sand and coarse gravel and has been 

 excavated to 10 feet below mean tide. 



A partial analysis of the buff clay from McConnell and 

 O'Brien clay bank at Yerplank is given below : 



Silica 50.92 



Alumina 26.87* 



Peroxide of iron 4 . 90 



Lime 2.52 



Magnesia 1.56 



Upper Blue clay. 



Lower Blue clay. 



Silica 



Alumina 



Peroxide of iron 



Lime 



Magnesia 



62.30 

 14.663 

 9.2 

 3.98 

 1.05 



57.74 

 26.31* 

 4.6 

 2.93 

 1.4 



* Alumina is probably too high.— H. Ries. 



