NEWARK ROCKS OF ROCKLAND COUNTY, N. Y. 15 



having an average elevation of from 100 to 200 feet above sea 

 level. With the appearance of the coarser and more resistant 

 beds the general elevation becomes greater, and in place of the 

 gently rolling lowland, there is a succession of ridges and valleys 

 following very closely the trend of the beds. The rock of all the 

 ridges is much alike. It is a coarse sandstone with some pebble- 

 bearing beds and occasional shale layers. The constituent peb- 

 bles are sandstone, quartzite, quartz, limestone, slate and feld- 

 spar, while there is an entire absence of granite, gneiss or schist. 

 Occasionally pebbles 5 inches in diameter occur. 



The charcteristics which were observed in the northern part 

 of the New Jersey belt persist in New York state. Beds of the 

 Stockton group occur beneath the trap sheet at Piermont, and 

 probably also along the west of the Palisade ridge as far north as 

 Blauveltville, though, owing to the heavy accumulations of gla- 

 cial drift within this area, exposures are rare. Between Piermont 

 and Nyack the trend of the rock is such as to carry them beneath 

 the Hudson river, and the beds exposed along the shore near 

 Nyack and farther north apparently belong to a horizon above 

 the Stockton group. 



In New York there are no beds which in lithologic character- 

 istics compare with the Lockatong group. The hard, black shales 

 and argillites typical of this subdivision do not occur. The con- 

 ditions favorable for their accumulation evidently did not prevail 

 in this region. There is, however, no evidence that sedimentation 

 did not take place in the New York area while the argillites were 

 being deposited in New Jersey and Pennsylvania. The arkose 

 sandstones here grade upward into red shales, sandstones or con- 

 glomerates which resemble lithologically the members of the 

 Brunswick group. 



The characteristics which distinguish the Brunswick beds in 

 Bergen county (N. J.) persist in Rockland county (N. Y.) Polit- 

 ical boundaries are not in this case at least geologic boundaries. 

 The description of the sandstones and conglomeratic layers given 

 above applies equally well to Bergen county or to Rockland 

 county. Overlying the gray arkose sandstone on either side of 



