New Species of-Devonioii Fossils. -141 



Trematospira costata angusta, n. var. 

 Plate IV, figs. 6, 7 



This variety of T. costata which occurs in the Birdsong shale 

 of Tennessee differs from the New York form chiefly in pro- 

 portion of leiigth to breadth. In New York, the shells are less 

 than half as long as wide, and each lateral slope bears five or 

 commonly six plications j in Tennessee, the length is about 

 three-fourths the width, and the lateral slopes have only five pli- 

 cations. This narrower and elongate form is therefore a clearlv 

 distinguished variety, though in all its other characters it agrees 

 fully with Hall's species. 



Dimensions: Length, 17 mm.; width, 22 mm.; thickness, 11 

 mm. 



Occurrence: Rather rare in the Birdsong shale at the old 

 Swayne's mill locality on Eiig Sandy River, Henry County. 



CLASS GASTROPODA 



FAMILY PLEUROTOMARIID^ 



Saffordella, n. gen. 



Diagnosis: Shell depressed subconical, consisting of a few 

 rapidly expanding whorls that are rounded subangular at the 

 periphery. Base convex, umbilicus small or lacking. Aper- 

 ture oblique, subquadrate, and deeply notched. Depth of slit 

 unknown. Slit-band distinctly defined by a sharply depressed 

 line along its upper and lower margins. Band broad, gently 

 convex, and situated entirely upon the upper slope of the whorl, 

 its lower margin not reaching quite to the periphery. The 

 growth-lines on the upper slope swing strongly backward to the 

 slit-band with a sigmoidal curvature, being convex forward near 

 the suture and concave forward near the band. On the lower 

 side they first run strongly forward and then recurve near the 

 base, but finally bend forward again upon entering the umbilical 

 depression. The lines of growth crossing the slit-band are 

 notable because their curvature is convex forward. 



In general appearance this genus most closely "resembles Eoto- 

 maria, from which it may have been derived. It is readily dis- 

 tinguished from the latter, however, by the characters of the 

 slit-band. In Eotomaria the band is concave, it is proportion- 



