68 NEW YORK STATE MUSEUM 



curving into the lateral margins which, in the pedicle valve, are 

 converging and little curved ; the posterior margin is, in the pedicle 

 valve, acutely rounded. The brachial valve approaches an ellipse 

 in outline, the anterior and posterior margins are subequally 

 rounded, and the lateral margins subparallel. Both valves are flat, 

 the pedicle valve with a low elevation that begins at the apex, 

 broadens rapidly and merges into the general surface about the 

 center of the valve. The brachial valve is more evenly rounded in 

 the posterior half ; the anterior half is also quite flat. The pedicle 

 valve shows indications of a low septum extending halfway to the 

 margin, the brachial valve one reaching two-thirds the length of the 

 valve. The growth-lines are fine, unequal and little prominent. 



Measurements. Length 12 mm, width 8 mm. 



Horizon and locality. Bertie waterlime, Litchfield, N. Y. 



Remarks. This species is rather common in the Eurypterus beds 

 about Litchfield. We have nine specimens in the space of 3 square 

 inches. It has also been cited as L. rectilatera Hall 1 from 

 the Bertie waterlime at Buffalo. The latter species is, however, a 

 type of the New Scotland limestone and while similar, differs 

 distinctly by its squarish posterior end. The occurrence of our 

 species in the Eurypterus beds of the Bertie waterlime together 

 with other marine forms testifies to the marine sedimentation of 

 the beds, hence its name. 



Lingula vicina no v. 



Plate 24, figures 11 and 12 



Description. Shell small, elongate-elliptical, high, two-thirds 

 as wide as long, widest at beginning of the anterior third. Anterior 

 margin well rounded, lateral margins converging in the -posterior 

 half, slightly convex, posterior margin acutely rounded. Brachial 

 valve relatively broader and less acute posteriorly. Valves high 

 for a Lingula, with a broad median ridge extending two-thirds of 

 the length of the valve. Septum on pedicle valve broad, traceable 

 nearly the full length of the valve, that of the brachial valve 

 narrower and shorter. Growth-lines very fine, distinctly bunched 

 in varices, giving the shell a more coarsely striated appearance. 



Measurements. Average size 9 by 5.5 mm; the largest specimen 

 observed measures 10 by 6 mm. 



1 I. P. Bishop, Geology of Erie County, N. Y. 49th Rep't N. Y. State 

 Geol. for 1895, p. 341. 1898. 



