Geoloyy of Huihoii County, JVeiv Jersey. 45 



is reported to be shown fai'tlier nortliWcird at Englewood. The 

 condition, however, of the sedimentary beds resting on the npper 

 surface of one of tlie trap-sheets is well shown on the western 

 slope of the First Newark Monntain at Feltville. * 



In the glacial drift covering Bergen Hill, Weehawken, etc., 

 are many boulders and large irregular masses of metamorphosed 

 shale or slate, identical with the rock outcropping beneath the 

 trap at Weehawken ; these boulders were doubtless derived from 

 the metamorphosed slate overlying the main sheet of trap in the 

 immediate vicinity. 



Minerals of the Trap. — The beautiful minerals obtained at 

 Bergen Hill during the construction of the railroad tunnels and 

 cuts, are familiar to all collectors. They are mainly zeolites, — 

 hydrous silicates of alumina and alkalies,- — and are the result of 

 the deposition of these substances, in varying proportions, in the 

 cavities and fissures of the trap, Avhither they have been carried 

 in solution by percolating waters, which, especially under the 

 influence of heat and j)ressure, have great solvent powers upon 

 the constituents of the trap, f 



Economic Importance of the Trap. — The fine-grained rock 

 along the eastern face of Bergen Hill, furnishes an excellent 

 material for paving and building, as it can be broken with ease 

 and certainty into blocks of the desired size and shape; Hudson 

 County produces each year many thousands of such paving-blocks, 

 and the demand will no doubt continue to increase. 



The fine-grained trap, when broken into small fragments, fur- 

 nishes one of the very best materials for macadamizing roads or 

 for railroad ballast; and the chips and waste from the manufac- 

 ture of paving and building-stones should be utilized for such 

 purposes. 



The value of the rock of the Palisade range, as a building- 

 stone, seems to be scarcely appreciated, although there are 

 several examples of its use for substantial edifices : the Stevens 

 Institute of Technology at Hoboken, and St. Joseph's and St. 

 Patrick's churches on the Hights, are constructed of this ma- 



* " On the Intrusive Nature of the Triassic Trap sheets of New Jersey." Amer. J. Sci.,Vol. 

 XV, p. 277, 1878. 

 t For further reference to the Bergen minerals, see note at the end of this article. 



