24 H. B. KUMMEL 



Point and the hypotenuse along the Hudson River. The south- 

 eastern boundary from Trenton northeastward to Staten Island 

 is for the most part formed by overlying beds, Cretaceous and 

 younger. Near Trenton, however, the underlying Philadel- 

 phia gneiss outcrops for a few miles. The waters of the Kill 

 von Kull, New York Bay and Hudson River form the boundary 

 from Staten Island northward. The northwestern boundary is 

 irregular and is formed entirely by older rocks — crystallines 

 and Paleozoic shales and limestones. Thegeneral position oRhese 

 rocks and their relations to the older and new formations are 

 shown in Fig. I. 



THE ROCKS 



The Newark series consists of sedimentary and igneous 

 rocks. The former are chiefly shales, sandstones and conglom- 

 erates ; the latter, diabase, to which the more general term trap 

 has usually been applied. Along the Delaware River (Fig. 2) 

 the sedimentary rocks are divisible, on lithological grounds, into 

 three groups, which have been called Stockton, Lockatong, and 

 Brunswick. 



Stockton group. — The basal beds of the series are found at 

 Trenton where they rest unconformably upon the older crystal- 

 line rocks. They consist of {a) coarse, more or less disinte- 

 grated arkose conglomerates ; (d) yellow, micaceous, feldspathic 

 sandstone ; (c) brown-red sandstones or freestones, and (d) 

 soft red argillaceous shales. These are interbedded and many 

 times repeated, a fact which indicates rapidly changing and 

 recurrent conditions of sedimentation. Although there are 

 many layers of red shale in this subdivision the characteristic 

 beds are the arkose conglomerates and sandstones, the latter of 

 which afford valuable building stones. 



In addition to the cross-bedded structure which often pre- 



the State Geologist of New Jersey for 1896, pp. 25 et seq. ; Annual Report of the 

 State Geologist of New Jersey for 1897, pp. 23 et seq.: Jour. Geol., Vol. V, pp. 

 541-562. A detailed account of the New York area will be published in the Annual 

 Report of the State Geologist of New York, and a briefer summary in the AnnuaL 

 Report of the State Geologist of New Jersey for 1898. 



