1898-1902 No. 32.] FOSSIL FAUNAS FROM SERIES B. 29 



will refrain from making any idenlificalion. From the oblique, highly 

 convex umbonal ridge, which terminates in a prominent, moderately 

 incurved beak expands anteriorly a very small wing and posteriorly a 

 rather large one. In the outline of this posterior wing there is possibly 

 a slight difference between my species and the original, the latter showing 

 a broadly sinuate margin just below the hinge-line, while the Ellesmere- 

 land-form seems to have a straight margin. As however, the dorso-post- 

 erior corner of the valve is not completely preserved, it is possible that 

 originally a slight curvature was present. 



The surface of the cast is marked by broad, not very strong con- 

 centric undulations, especially promment on the umbonal ridge. An indi- 

 cation of a radiating striation may also be seen in this part of the shell 

 and better defined, at the margin of the posterior wing. 



Occurrence: B, upper part, over the fragment-limestone, Valley 



south of Borgen. 



Nuculidae. 

 NuculaC?) sp. 

 PI. VIII, fig. 7. 



Two casts of a relatively small and flat oblong lamellibranch, prob- 

 ably belonging to a Nucida, were found. From the quite prominent 

 beak the dorsal margins slope gradually, at the anterior and posterior 

 extremities curving strongly and meeting in very slightly rounded basal 

 margin. Greatest depth of the valve about one third of the height. On 

 the surface, a rather faint concentric striation or undulation is visible. 



The malerial to hand of this form is too scanty for any exact 

 determination. Forms that in some varieties come very near to it are 

 Numla randalli Hall and N. lirata Conrad, both known from the 

 Hamilton of New York (see Pal. New York, vol. 5, part 1, Lamellibranchi- 

 ata, II, p. 315—316). 



Occurrence: B, upper part, near the fragment-limestone, Valley 

 south of Borgen. 



Gastropoda. 

 A spidobranchin a • 

 Marchisoniidae. 

 Hormotoma sp. 

 In some large pieces of a fine-grained brownish-grey limestone 

 occur a number of casts of a small and slender gasteropod, too fragmen- 

 tary for any specific identification. They seem to be much like a form 



