49 
Formation and Locality . In the Leray beds of the Black 
River at Rockland. 
Lingula narrawayi n. sp. 
Plate III, figure 4 
The shell is subspatulate in general outline and inclined to 
be convex. A somewhat sloping surface, varying from rounded 
to plane, on the top of the brachial valve, forms an isosceles 
triangle extending with the apex at the beak to a rounded base 
at the anterior margin. The brachial valve is oval, pedicle 
valve ovate, beak acuminate, and the anterior margin rounded. 
The ratio of the maximum length to the maximum width of the 
average shell is about as 5 to 3, the widest part being a little in 
front of the middle. From this point to the front margin the 
sides are almost parallel; toward the beak, however, they con- 
verge more rapidly. The pedicle valve, particularly, has a very 
acuminate beak, and from its average length, which is somewhat 
greater than that of the other valve, it is probable that the beak 
projects beyond that of the brachial valve. No specimen was 
found having the two valves together. The largest pedicle 
valve observed shows a broken scar of a long septum extending 
anteriorly two-thirds the length of the shell, but otherwise the 
markings of the interior are very obscure. 
The surface is covered with fine, concentric striae, and some 
specimens show an exceedingly minute radial striation. 
The shell is punctate and evidently extremely thin and 
tenuous, as all of the larger shells are much wrinkled. 
The specimens are very small, the largest pedicle valve 
found measuring only 10 mm. in length, and 6 mm. in width at 
the widest place; the largest brachial valve found is 8 mm. in 
length and 4^ mm. in width; the average shell being only 5 mm. 
in length and 3 mm. in width. 
Lingula narrawayi appears to be distinct from any described 
species of Lingula. It is similar in shape to Lingula daphne 
Billings, and Lingula riciniformis Hall, but is a much thinner 
shell, and differs from them in details of surface sculpture. 
The pedicle valve, too, is somewhat longer and narrower than 
that of either of these forms. 
19686-41 
