MOLLUSCA. 477 



the Navesink in G. C. Schanck's pits near Marlboro, a locality 

 less than one-foitrth of a mile from that which has furnished the 

 Survey material. The species has been detected at but one 

 locality in the Navesink, in the recent collections of the Survey. 

 It is probable that Whitfield's specimens were from the top of 

 the Wenonah rather than from the base of the Navesink, since 

 the Wenonah was exposed in the marl pits mentioned, and many 

 species were described from that horizon at that locality are 

 now known to belong in the Wenonah fauna. 



Formation and locality. — Wenonah sand, near Marlboro 

 (130) ; Navesink marl, near Red Bank (120). 



Geographic distribution. — New Jersey, Mississippi. 



Pecten parvus (Wliitfield). 



Plate L., Figs. 5-6. 



1886. Camptonectes parvus Whitf., Pal. N. J., vol. i 

 (Monog. U. S. G. S., vol. 9), p. 55, pi. 8, figs. 1-2. 



Description. — "Shell quite small, the only specimen observed 

 measuring only about three-tenths of an inch in height. Outline 

 subcircular and (the left valve) convex, moderately elevated on 

 the umbo and somewhat regularly declining in convexity, toward 

 the front ; anterior auriculation proportionally large and vertically 

 striated with lamellose stria: parallel to the anterior margin. Sur- 

 face of the shell polished and marked with numerous interrupted 

 impressed strias, the spaces between the striae being flattened and 

 crossed by very faint lines of growth." (Whitfield.) 



Remarks. — Whitfield reports having seen but a single speci- 

 men of this small species, and no further examples have come to 

 light in the more recent collections of the survey. The type is 

 probably from some portion of the Navesink marl, although the 

 horizon cannot be determined with any great degree of certainty. 



Formation and locality. — Navesink marl ?, Freehold (Whit- 

 field). 



Geographic distribution. — New Jersey. 



