SWALLOW — DESCRIPTION OF NEW FOSSILS. 97 



gin, marked with a broad shallow sinus from the umbo to the 

 middle of the ventral margin; beaks nearly terminal, proxi- 

 mate; anterior end narrow, sharply rounded in the middle; 

 posterior end wide, sharply rounded at the extremity, which 

 is above the middle ; ventral margin slightly concave in the 

 middle ; cardinal margin oblique, convex ; surface marked 

 with sharp, unequal, concentric plications. 



Length, .41 ; height, .25 ; thickness, .19. 



This fossil resembles, in its size and form, the Cyp. trans- 

 versa of De Koninck, but its markings are very different, and 

 like those of Cyp. squamifera of Prof. Phillips ; but the shell 

 is less, wider at the posterior extremity, and the beaks are 

 not so near the end. 



It was obtained from the Chouteau Limestone of Cooper 

 county, Missouri. 



Pecten Broadheadii. 



Shell varying from small to medium in size, broad ovate ; 

 costse ornamented with vaulted scales. Left valve very con- 

 vex, regularly arched ; umbo large ; beak small ; anterior wing 

 sharply defined, triangular ; separated from the margin by a 

 deep angular sinus ; anterior extremity acute : posterior wing 

 obscurely defined, triangular; obtuse at the outer extremity; 

 separated from the margin by a shallow rounded sinus. Sur- 

 face marked with sharp radiating costa?, which are ornament- 

 ed with concentric stria 3 , and, towards the margins, with 

 vaulted scales, shaped like sections of curved, infundibuliform 

 tubes. Right valve not known. 



This beautiful fossil was discovered in the Upper Coal 

 Measures of Harrison county, Missouri, by Mr. Broadhead. 



Pinna Missouriensis. 



Shell thin, long-lanceolate, subquadrilateral, more or less 

 compressed and costate. interior margin straight or convex, 

 and the posterior straight or concave ; valves usually more 

 convex on the anterior slope. Surface, on the middle and 

 posterior slopes, marked with about twenty large rounded, 

 radiating plications, which are crossed by unequal sub- 

 concentric, oblique folds and striae, curving from the an 

 terior slope, and becoming obsolete towards the posterior 

 margin. 



This fossil somewhat resembles the P. flabelliformis of 

 Martin ; but it is less compressed, more elongate, and very 

 differently marked. 



It is abundant in the Ste. Genevieve Limestone of Missouri 

 and Illinois. 



