154 CLAYS AND CLAY INDUSTRY. 



No. V. A reddish quartz sand. 



No. IV. Black, laminated sand and clay, strongly glauconitic 

 to the southwest, but less so* to the northeast. 



No. III. Vari-colored sands, locally with thin clay laminae and 

 lenses. 



No. II. Black clay, weathering to' a chocolate color, and non- 

 glauconitic. 



No. I. Black, sandy clay, notably glauconitic at top and bot- 

 tom, weathering to a cinnamon brown. 

 The total thickness in Monmouth county is about 230 feet. 



CIvAY MARL V (WENONAH SAND). 



This formation is in general a reddish-brown or black sand,, 

 sometimes strongly micaceous and often having a peculiar mix- 

 ture of pinkish, brown and gray sand grains, which give it a 

 characteristic color. Locally it is distinctly laminated with thin- 

 seams of black or chocolate-colored clay, but these are never, so- 

 far as seen, commercially important. It is somewhat ferruginous, 

 and is not infrequently cemented to ironstone, but less commonly" 

 so than the lower sand bed, Clay Marl III. It contains a small 

 amount of glauconite (greensand marl), but except near its top, 

 this element is not apparent save upon close examination. Deep 

 exposures, particularly in the upper portion of the formation, 

 often show large pockets of white sand, which are sometimes 

 clean sand, and sometimes, contain pellets of a hard white clay 

 giving the sand an arkose appearance. This phase is particularly- 

 characteristic of the upper 2 to 10 feet, and renders the sand 

 quite compact. These upper layers generally contain very coarse 

 grains of quartz sand, and are also not infrequently somewhat 

 cemented by iron, which has been leached from the overlying" 

 marl beds. 



At the very top of Clay Marl V, in the upper few feet of this 

 "arkose" sand, there is generally found a fossil bed from 1 to 4 

 feet in thickness composed largely of the large shell Gryphcca 

 vesicularis. The fossils are thickly imbedded in a matrix of 

 clayey sand in which there is an increasing amount of marL 



