rl50 NEW YORK STATE MUSEUM 



diorite, Cortiandt series (norite, diorite, etc.), Newark diabase. 

 The remaining rocks of igneous origin, occurring in areas too 

 small to be separately named may, for our i^resent purpose, be 

 grouped as granites. 



QUARRY INDUSTRY OF THE AREA 



PRETIOLS PUBLICATIONS 



Prof. J. S. Newberry, in liis report on Building and ornamental 

 stones, Philadelphia exposition, 1876, discussed at some length 

 the Tuckahoe and Pleasantville quarries, and their product. 

 The 10th census report on the stone quarry industrij contains short 

 notes on the marble quarries and a brief mention of the Lefurgy 

 quarry (in Fordham gneiss) at Hastings. In addition, however, 

 this report contains an exceedingly valuable and comprehensive 

 paper by Dr A. A. Julien on" Stone construction in New York city 

 and the vicinity," with detailed information regarding the dura- 

 bility, etc. of all stones, domestic or foreign, used here. In his 

 two reports on the Building stone of New York state, published 

 as bulletins 3 and 10 of the New York state museum. Prof. J. C. 

 Smock describes the quarries of the entire state in great detail, 

 giving physical and chemical data in bulletin 10. These reports, 

 abstracts of which have appeared in bulletin 15 of the New York 

 state museum, contain the best descriptions yet published of 

 the quarries and quarry industry in Westchester county, being 

 defective only in regard to the Yonkers gneiss, quarrying in 

 which was not actually begun till several years after the pub- 

 lication of the bulletins. All these reports, however, suffer 

 from one common and unavoidable defect. At the time at 

 which they were written the geologic structure of the area 

 had not been made out with any degree of certainty, and the re- 

 ports consequently err in grouping together quarries which are 

 worked in entirely different geologic formations. For this rea- 

 son, it has been in some instances extremely difficult to identify 

 the material on which the tests quoted were actually made. 



A report on the geology of Orange county by Dr Heinrich 

 Ries, published in the loth report of the New York state geolo- 

 gist, contains notes on the quarry industry in Orange county. 



