THE UPPER CRETACEOUS OF NEW JERSEY 77 



excluded. In the southern counties the Hazlet sands correspond only 

 with Knapp's Columbus and Marshalltown, all of the Wenonah being 

 excluded. The line, therefore, between the Matawan and Monmouth, 

 as these two divisions were defined in 1897, i s a nne running diagon- 

 ally across Knapp's Wenonah sand, from near the summit of that 

 formation at Atlantic Highlands to its base in Gloucester and Salem 

 Counties. This lack of agreement between the two interpretations 

 was apparently due to Clark's interpretation of the relations of the 

 coarse, quartz- sand phase of the Wenonah which he called the Mount 

 Laurel sand. In regard to this formation he said: 



They have a thickness of about 5 feet in the vicinity of Atlantic Highlands, 

 which slowly increases to the southward, until in the region to the east of Phila- 

 delphia they have increased to over 25 feet. Beyond that point they increase 

 more rapidly throughout the southern counties, reaching 50 feet in Gloucester 

 County and fully 80 feet in the vicinity of Salem. 1 



In New Jersey the lithological change at the top of the Wenonah 

 is much more marked than that at its base, and for this reason the 

 Wenonah sand was grouped by Knapp and Kiimmel 2 with the 

 underlying rather than the overlying beds. In effect, therefore, two 

 positions for a major dividing line in this portion of the section have 

 been suggested : (a) diagonally across the Wenonah sand ; and (b) at 

 the top of the Wenonah sand. 



The recent paleontological studies cast some light upon this prob- 

 lem, even although they do not definitely settle it. 



The Wenonah sand, so far as known at present, carries two 

 different faunas. One of these has been found in Monmouth County, 

 and at two localities from which extensive collections have been made 

 over one hundred species have been recognized. This is very differ- 

 ent from that in the overlying Navesink marl, and for the present will 

 be referred to as the Wenonah fauna, although ultimately it may be 

 best to give it a different name. The other fauna occurs in Gloucester 

 and Salem Counties, and will be described in connection with that 

 of the Navesink marl. 



At one of the localities where the Wenonah fauna has been found 

 the fossils occur in a coarse ferruginous sand at a distance of 9 feet 



1 Annual Report of the State Geologist of New Jersey, 1897, p. 183; also Bulletin 

 of the Geological Society of America, Vol. VIII, p. 334. 



2 Loc. cit. 



