49 



Description. — Elongate, conical ; anterior angles rounded ; front margin 

 nearly straight or gently convex ; sides somewiiat straight and parallel in 

 the lower half, then converging with a very moderate curve to the beaks ; 

 apex acutely rounded. Both valves appear to be very slightly convex and 

 with a slight barely perceptible concavity near the sides. Surface when 

 perfect to the naked eye nearly smooth and with a glistening lustre ; under the 

 lens shewing very fine longituduial striae ; these become more apparent when 

 the shell is partially exfoliated. There are also numerous obscure undu- 

 lations of growth. One of the valves shews in the cast of the interior a 

 strong groove along the median line sometimes extending nearly the whole 

 length of the shell. Colour of shell light brown. 



Length of largest specimen seen 9 lines ; width at one fourth the length 

 from the base 5 lines at one fourth the length from the apex 3§ lines. 



Specimens from 5 lines up to 9 lines in length occur associated together 

 in the same locality. 



This species resembles L. Progne but is of a more nearly conical shape, 

 the side commencing to converge towards the apex from a point about the 

 middle or a little below. 



Locality and Formation. — Near Olivier's Mills on the River Bayonne. 

 Lower part of Trenton limestone. 



Collector. — J. Richardson. 



LiNGULA Philomela. (N. sp.) 



Fig. 53. 



Description. — Very elongate, oval ; width a little less than half the 

 length ; front margin rather narrowly rounded with a small space in the 

 middle straight or sinuate ; sides for about two thirds the length straight 

 or very gently convex ; the apical extremity appears to be obtusely angu- 

 lar but this still remains doubtful as no specimens with this part 

 perfect have been collected. The shell is rather strongly convex, most 

 prominent at or about the mid-length. There is shallow concave sinus extend- 

 ing all along the median line from near the apex to the front margin. 

 Surface with fine crowded imbricating striae of variable size, the smaller 

 just visible to the naked eye and the larger partaking of the nature of 

 squamose interruptions of growth. Colour in the black limestone black. 

 A specimen in grey limestone shewing the interior in a state of exfoliation 

 is light greyish-brown, but this may be owing to some circumstance in the 

 fossilization of the shell. 



Length 16 lines ; width 7 lines. 



Locality and Formation. — Montmorenci Falls, and Island of Montreal. 

 Trenton limestone. 



Collectors. — Sir W. E. Logan, J. Richardson. 



