LOWER SILURIC SHALES OF THE MOHAWK VALLEY IO7 



or sulci are present on the anterior third of the valve; one, very 

 narrow, between the anterior umbonal ridge and the nasute anterior 

 projection; the other running obliquely backwards from the anterior 

 side of the umbones, to the basal margin, where it produces a slight 

 sinuosity. Surface marked with irregular concentric wrinkles, 

 which are generally most prominent over the more gibbous parts 

 of the valve. 



Length of best specimen seen, 2.4 inches ; greatest height, measur- 

 ing vertically across the anterior end of the posterior third, 1.15 

 inches ; from a point back of umbones to basal margin, i inch ; from 

 highest point of umbones to antero-basal portion, i inch ; length of 

 nasute extension of anterior end, from its extremity to the anterior 

 side of umbones, .38 inch; convexity of one valve, .5 inch. 



This species differs from the typical forms of this genus in that 

 the posterior half of the valves is miuch wider (higher) than the 

 anterior. The generic reference is probably only temporary pending 

 a revision of the shells of this family. Of described species only 

 C . s c a p h a Hall and Whitfield, bears any resemblance. The new 

 species is readily distinguished by its greater width posteriorly, 

 greater convexity, more prominent umbones, smaller lunule, much 

 more acute and prolonged anterior end, less distinct mesial sulcus, 

 and somewhat different surface markings. Closer allies are found 

 among the undescribed species in the Ulrich collection at the United 

 States National Museum. 



Formation and locality. This species is rare, and hitherto has 

 been found only in association with Whiteavesia Cincin- 

 nati ens is (Hall and Whitfield) in a limestone bed exposed in 

 the banks of the Ohio at Covington, Ky. This bed lies near the top 

 of the Bromley shale, a formation corresponding very nearly to the 

 Hermitage formation of middle Tennessee and central Kentucky. 

 Correlating with New York formations its age would be early 

 Trenton. 



Holotype. U. S. Nat. Mus. Cat. no. 47314. 



Doctor Ulrich observes that the Snake hill specimen is smaller 

 and somewhat shorter, the latter perhaps due to pressure, but other- 

 wise undistinguishable from the Cincinnati specimens. 



Saffordia ulrichi nov. 



PI. 6, fig. 17, 18 



For a great many years there has been in the State Museum a 

 large fossil shell which had been sent in from one of the "blue- 

 stone " quarries at Schenectady ^ and which was considered as a 



1 It is labeled : " Hudson River group, from Schenectada, near the 

 College. From J. L. Coon." 



