Cinc'uinatian and Lcxingion Fossils 43, 



Greendale north of Lexington, and between Million and Valley 

 View. 



The narrower, more typical forms of Rafjiicsqitiiia ivinchcstcr- 

 ensis are accompanied by others in which the width is somewhat 

 greater, the posterior outline, however, remaining quadrate (plate 

 V, figs. 14, 15 A,B). In these specimens the length usually equals 

 nine-tenths of the width or less. These specimens usually have a 

 less convex appearance, especially anteriorly. In a specimen 35 

 mm. long and 39 mm. wide, the convexity was 7 mm., and the 

 thickness of the shell through the valves 4.5 mm. In these speci- 

 mens the radiating striae of the pedicel valve are distinctly finer, 

 especially along the posterior half of the shell, although becoming 

 larger and alternating in size near and anterior to the middle. 

 The striae of the brachial valve also are finer. For these flatter, 

 finely striated forms, the term filistriata has been selected. As a 

 matter of fact, some of the narrower, more convex specimens, re- 

 sembling typical Rafiticsquina wi)ichcsfc}rnsis in form, have 

 numerous fine striae, but intermediate forms are to be expected in 

 any attempt to differentiate the Rafincsquinae. 



Rafincsquina fracta, com])ared with Rafiiiesqiiina ivinchcstcr- 

 ensis, is a larger, flatter, and much thinner shell, although possess- 

 ing a similar outline. 



Specimens of Rafincsquina from the Eden formation, between 

 Rogers Gap and Sadieville, agree with the variety filistriata in 

 outline, but are thinner, and there is a distinct difference in the 

 size of the striae, one to three finer striae being intercalated be- 

 tween the much more prominent primary ones. A similar alterna- 

 tion is faintly indicated on the brachial valve. The median 

 plication may be slightly more distinct. 



Rafincsquina declivis, James. 



(Plate II, fig. 4; Plate V, figs, u A.B,C,D.) 



The following description of Rafincsquina declivis, under the 

 generic term StropJwuicna, was published by U. P. James in the 

 Cincinnati Quarterly Journal of Science, vol. i, p. 240, in 1874: 



This shell is remarkable for the manner in which it is arched or bent 

 over. Cardinal line of the ventral valve straight; area narrow; beak slightly- 

 projecting; cardinal line pointed at the extremities, extending, apparently, be- 

 yond the width of the shell below (owing to the sudden depression or curve of 

 the lateral margins, directly forward of the points of the cardinal line, it has 



