42 Aug. F. Focrste 



and the granules are more or less elongated, as though the bases of 

 setae. While the granules are scattered, there is a tendency toward 

 arrangement in more or less radiating lines. Crania granulosa 

 occurs in the northern states of the Mississippi valley in strata 

 which are equivalent to the lower strata exposed at High Bridge, 

 Kentucky, and at Wells creek, in Tennessee. The Wells creek 

 specimens of Crania therefore may be much more closely related 

 to Crania granulosa than their size and general outline would 

 indicate. 



Rafinesquina winchesterensis, sp. nov. 



(Plate V, figs. 13 A, B.C.) 



In the Greendale division of the Cynthiana formation, east 

 of the Cincinnati geanticline, between Nicholas county and Madi- 

 son county, in Kentucky, forms of Rafinesquina with relatively 

 narrow widths are common. 



In the form for which the term Rafinesquina zvinchesterensis 

 has been selected, the posterior outline is quadrate, the sides either 

 being parallel or converging slightly toward the hinge-line. Along 

 the anterior margin, the outline is evenly rounded. In the typical 

 forms, the length nearly equals, or even slightly exceeds the width, 

 producing an elongate appearance. However, specimens in which 

 the length equals only nine-tenths of the width are common. The 

 earlier stages of the shell, including about two-thirds of its length 

 when mature, are moderately convex, but the anterior third of the 

 more mature shell is curved downward so as to give a decidedly 

 convex appearance on anterior or lateral view. In one specimen, 

 31 mm. long and 32 mm. wide, the convexity is 10 mm. The 

 hinge-area of the pedicel valve is large; 2 mm. in height at the 

 beak, and parallel to the plane of the brachial valve. In the 

 typical shells, the radiating striations alternate more or less in size, 

 especially from the umbo to one-third the length of the shell from 

 the beak. The muscular area of the pedicel valve is indistinctly 

 defined anteriorly. The muscular area of the brachial valve pre- 

 sents the same features as most forms of Rafinesquiiui from the 

 overlying Cincinnatian rocks. In specimens 31 mm. long, the 

 thickness of the shell through the valves is 6 to 7 mm. 



Forms possessing these characteristics are found between 

 Pleasant Valley and Millersburg, between Colby and Winchester, at 



