484 CRETACEOUS PALEONTOLOGY. 



marl, Atlantic Highlands (108), Crosswicks Creek (147), Mull- 

 ica Hill (169), Holmdel and Freehold (Whitfield). 



Geographic distribulion. — New Jersey, Alabama, Mississippi, 

 Texas. 



Family SPONDYLIDAE. 



Genus Plicatu^a Lamark. 



Plicatula urticosa (Morton). 



Plate LI.I., Pigs. 1-2. 



1833. Ostrea urticosa Mort., Am. Jour. Sci., ist ser., vol. 23, 



p. 293, vol. 24, pi. 10, fig. 2. 



1834. Plicatula urticosa Mort., Synop. Org. Rem. Cret. Gr. U. 



S., p. 62, pi. 10, fig. 2. 

 1 861. Plicatula urticosa Gabb, Synop. Moll. Cret. Form., p. 



225 (169). 

 1864. Plicatula- urticosa Meek, Check List Inv. Foss. N. A., 



Cret. and Jur., p. 7. 

 1868. Plicatula urticosa Con., Cook's Geol. N. J., p. 724. 

 1886. Plicatula urticosa Whitf., Pal. N. J., vol. i (Monog. U. 



S. G. S., vol. 9), p. 61, pi. 9, figs. 1-2. 

 1905. Plicatula urticosa Johns., Proc. Acad. Nat. Sci. Phil. 



(1905), p. 12. 



Description. — "Shell irregularly oval in outline and obliquely 

 curved, biconvex or plano-convex, marked by strong, somewhat 

 angular radiating and bifurcating plications, usually much 

 stronger and less numerous on the lower than on the upper valve, 

 and crossed by strong projecting concentric lamella, which are 

 elevated and often form thin, flat spines on the crest of the radi- 

 ating plications of greater or less length, which give a very rough 

 and spiney surface to- the shell, resembling' that of Spondylus. 

 Muscular impression moderate; teeth not observed." (Whitfield.) 



Remarks .—^\ns species has not been met with abundantly in 

 the recent collections of the Survey. It differs from that form 

 described in the present report as P. mullicanensis in its more 

 irregular form and in its much more rugose markings. 



