(jeohxiji iif I^ii-li 1110)1(1 Cniui/i/. y. )'. 171 



The white tire-chiy is sometimes tissuciatod with the so-Ciilled 

 "kaolin." This material, whieh is very incorrectly named, 

 consists of. a. mixture of white ([uartz sand with small amounts 

 of white mica and clay, and sometimes grains of feldspar : it is 

 known as "kaolin" throughout the clay district of New Jersey, 

 but of course is not a kaolin, as this term is only properly ap- 

 plied to clays formed by the decomposition of feldspathic rocks 

 in place. An analysis of this substance taken from the pits of 

 C. A. Campbell & Co.. near Kossville. made in the laboratory 

 of the (xeological Survey of Xew Jersey, and published in their 

 Report on Clays, 1878. is as follows : — 



SiO, 



U2. ro 



per cent. 



Al.,0, 



5. ro 





H„() 



0. TO 





kJo 



O.oo 







!l!).-Jt5 



])er cent, 



From this association of •' kaolin " and tire-clay, it is supposed 

 that the pits hitherto opened on 8taten Island belong to the 

 South Amboy tire-clay bed. These excavations are all south of 

 Rossville, and quite close together. Assuming that these clays 

 do belong to tliis bed, then those which outcrop north of that 

 village may indicate the position of the Woodbridge fire-clay 

 bed, which lies north of the tirst-mentiouei one in Middlesex 

 Co., X. J. From its position, the clay near Prince's Bay will 

 then belong to the South Amboy bed, and that at Gilford's to 

 the AA'oodbridge bed. But these are merely suppositions. So 

 far as is know^i, the strata immediately underlying Tottenville 

 and the extreme southern end of the island consist of sands only, 

 no clay having yet been dug in that vicinity. 



The extension of this formation to the east is indicated by an 

 outcrop of buff-colored clay on the shore of the Lower Bay, 

 about one half-mile south of the Elm-Tree Lighthouse. It will 

 be noticed that all the pits from which clay has been taken are 

 in the region between Rossville and Kreischerville. This does 

 not prove by any means that clay occurs only in that neighbor- 

 hood ; on the contrary, the probability is that the beds extend 

 interruptedly across the count}', but are deeply covered by the 



