DESCRIPTIVE NOTES 



OF 



Quarry Districts and Quarries. 



I -CRYSTALLINE BOOKS. 



GRANITES, SYENITES, GNEISSES, MICA SCHIST. 



Beginning at the south, with the quarries in rocks of this group, 

 the New York or Manhattan Island gneisses have afforded a 

 large amount of stone for common building work. These gneisses 

 are mostly of the micaceous variety ; and they are found in thin 

 beds, dipping at high angles generally and to the east-south-east or 

 west-north-west. Owing to the large percentage of mica they are 

 not so strong and durable as the true gneisses and granite ; and are apt 

 to flake oif and disintegrate on long exposure. Some of the more 

 feldspathic beds and the granitic veins and dikes afford a stronger 

 and better material. But the general mass is at best of an inferior 

 character. The excavations for streets and the grading of hills has 

 yielded a very large amount of stone for foundations and inner walls. 

 The Forty -second street reservoir is an example of the best of the 

 island gneiss. St. Matthews's Lutheran Church, Broome street, is 

 another. 



Fordham, Westchester County. — St. John's College has a 

 quarry on its property nearly a half mile east of the college, and on 

 the corner of the Boulevard and Pel ham avenue. There are two 

 openings, of which the larger, measures, approximately 140 feet by 

 50 feet and 25 feet deep. The strata dip 82° to 86° S. 65° E. The 

 stone is a micaceous gneiss, consisting of brown-black mica in lamiuse, 

 parallel with the bedding and alternating with quartz and feldspar. 

 It has a bluish-gray shade of color, and hence is known as "blue- 

 stone." Owing to the mica the stone splits readily in planes parallel to 

 the bedding, and is squared easily into blocks for heavy walls. And 

 blocks 25 feet long, 6 feet wide can here be obtained. There is no water 



