io CRETACEOUS AND TERTIARY FISH. 



series of Cook, although in the southwestern proticn of the 

 State he referred these beds to the Navesink (Lower) marl. It 

 was included in Clark's Hazlett sands, a sub-division of his 

 Matawan. 



The Wenonah and Mount Laurel sands. — Above the Marshall- 

 town clay-marl there is a considerable thickness of sand regarding 

 which there has been some difference of opinion. The terms 

 Wenonah and Mount Laurel have both been applied to it in whole 

 or in part. Lithologically these sand layers are not sharply dif- 

 ferentiated from each other, although the lower part (Wenonah) 

 is generally a fine micaceous sand and the upper part (Mount 

 Laurel) is coarser and contains considerable greensand. Pale- 

 ontologically, however, they are quite distinct. The Wenonah 

 fauna is largely recurrent from the Woodbury, with compara- 

 tively few prominent species common either to the Marshalltown 

 below or the Mount Laurel and Navesink above. The same 

 elements are prominent again still higher in the Red Bank. The 

 Mount Laurel invertebrate fauna is identical with that of the 

 Navesink above, and is closely allied to the Marshalltown, but 

 contains a foreign element, chief among which is the cephalopod 

 Belemnitella americana and the brachiopod Terebratella plicata r 

 so that the indistinct lithological line between the Wenonah sand 

 and Mount Laurel sand is of considerable paleontological sig- 

 nificance. The combined thickness of these formations is -40 to* 

 80 feet, the Mount Laurel being limited to a. very thin bed at 

 Atlantic Highlands (Cook's sand-marl) but increasing much in 

 thickness toward the southwest. The Wenonah sand is the 

 highest bed correlated with the Matawan of Maryland, while the 

 Mount Laurel is the base of the Monmouth. 



Navesink marl. — The Navesink marl consists of greensand 

 marl, mixed with varying amounts of quartz sand and fine earth, 

 the latter of which contains much carbonate of lime in a powdery 

 state. Where purest the marl has a dark-green or bluish-black 

 color. The upper part of the bed contains progressively less 

 greensand and is more clayey. The invertebrate fauna is large 

 (121 species, Weller), and is allied with that of the Marshall- 

 town and Merchantville beds, while the characteristic forms of 



