152 



NEW YORK STATE MUSEUM 



Tests of the trap by the bureau of research, State Department of 

 Highways, gave the following results on a number of samples : 



specific gravity 



Weight, pounds for each cubic 



foot 



Water absorbed, pounds for 



each cubic foot 



Per cent of wear 



Hardness 



Toughness 



I 





3 



4 



5 



6 



7 



2.96 



2.97 



2.88 



2.81 



2.92 



2.96 



2.98 



185 



186 



180 



176 



183 



1S5 



186 



.68 



.17 



.40 



■44 



.26 



.22 



■ 23 



3.6 



2,6 



2.7 



2 . 1 



2.6 



3-1 



2.8 



17.8 



17.9 



17.8 



18.6 



18.2 



17.8 



18.2 



14.5 



17 



16.5 



22.5 



17 



16 



22.5 



2.82 

 176 



■ 70 



4. 



18.2 

 I4-S 



In the near future the quarrying of trap from the face of the Pali- 

 sades will probably be discontinued, as the river front is to be incor- 

 porated in the Palisades Interstate Park. 



The property of the Manhattan Trap Rock Co., on the southeast- 

 erly face of Hiook mountain, has already been taken over for pur- 

 poses of the park and the crushing plant dismantled. The other 

 quarries in this section are owned by the Rockland Lake Trap Co., 

 the Clinton Point Stone Co. and the Haverstraw Crushed Stone Co. 

 They are still operative (1914) but it is understood that negotiations 

 for their purchase have been begun. With their acquisition the in- 

 dustry along the riverside, which is the most advantageously situ- 

 ated for the econO'mic production and shipment oi crushed trap will 

 come to a definite end. The supply then must co'me from some of 

 the inland quarries or from the New Jersey and Connecticut trap 

 areas, in either case probably at an increase in cost. 



The present quarries are well equipped and capable of turning out 

 a large output at a low cost. The largest of them is owned by the 

 Rockland Lake Trap Co., where there is a face of 2000 feet and 500 

 feet or more high. The rock is broken down in enormous quantity 

 by drilling and blasting, loaded onto cars by steam shovels and 

 crushed in the plants at the riverside whence it is loaded into barges 

 for transport to New York and the other markets on the river and 

 coast. 



LADENTOWN, ROCKLAND COUNTY 



Trap is exposed over a considerable area south of Ladentown and 

 west of the branch railroad from Spring Valley to Haverstraw. 

 The area is in line with the course of the Palisades intrusion from 

 Haverstraw to Mount Ivy but is separated from the latter by a 

 stretch of over a mile in which the rock does not appear at the 

 surface. The trap also differs somewhat in appearance from the 

 Palisades diabase. As mapped by Kummel, the area measures 



