668 CRETACEOUS PALEONTOLOGY. 



1892. Pleurotrema solariformis Whitf., Pal. N. J., vol. 2 

 (Monog. U..S. G. S., vol. 18), p. 180, pi. 22, figs. 

 10-14. 



i 



Description. "Shell of more than moderate size, the largest 

 example before me measuring almost 2% inches in its greatest 

 diameter, by I ^ inches in height, and is- an internal cast with the 

 apical volutions absent. Volutions as preserved in this specimen, 

 four in number, and probably one and a half or two absent; 

 spire low, conical, the sides forming an angle of about 90, and 

 the volutions flattened on their upper surfaces in a line with the 

 apical angle ; sutures well marked but not deep, indicating a shell 

 of only moderate thickness ; base of the volutions flattened-con- 

 vex, leaving the peripheral angle somewhat acutely rounded ; the 

 inner part of the base of the volution rapidly slopes into the 

 broad, open perspective umbilicus, forming a rounded funnel- 

 shaped cavity in which all the volutions are seen, but with a very 

 slightly marked suture line separating them. Section of the 

 volution rhombically elongate-ovate, the umbilical part being at- 

 tenuated where it joins the preceding volution ; along the middle 

 of the outer volution there occurs an elevated ridge, which pre- 

 sents the appearance of a series of interrupted nodes of an 

 elongate-oval shape, as if the shell had been provided with a line 

 of oval openings occupying this position, but filling up beyond the 

 outer half of the volution ; surface of the shell unknown." (Whit- 

 field.) 



Remarks. Members of this species were originally included 

 by Gabb in his Architectonica abbotti, now referred to Pleuroto- 

 maria crotaloides, the types of which are from the Navesink marl 

 at Mullica Hill. Whitfield separated the Timber Creek specimens 

 as a distinct species, and established the new genus Pleurotrema 

 for its reception. 



Formation and locality. Vincentown limesand. Timber 

 Creek (Whitfield). 



Geographic distribution. New Jersey. 



