NORTHUMBERLAND AND DURHAM. 2C7 



dubius, originally applied to this shell by Schlotheim, has priority 

 of all others, even of the now well-known Sowerbian epithet 

 obscurus. It is therefore necessary to adopt this so-long-neg- 

 lected name. 



Under this name there may be very conveniently placed the 

 following species of authors: — Axinus obscurus, Sow.; A. par- 

 vus, pusillus, productus, undatus, elongatus, rotundatus, and Lu- 

 cina minima, Brown; Schizodus ScJdotheimi, Geinitz, and Schi- 

 zodus truncatus. King. 



Bemarks on Mr. Binneifs Specimens, — Two small casts of A:c. 

 parvus belong without doubt to the above. — A. productus re- 

 sembles the form which King has separated under the specific 

 name truncatus. It is rather more produced in front, and more 

 truncated behind. It cannot claim to be more than a regular 

 growth of dubius. — A. undatus and A. elongatus belong also to 

 the above. They present no peculiar characters. A. pusillus 

 and Lucina minima appear to be the young of the foregoing- 

 species. 



In the " Perm. Mon.," under four specific names (pi. 15. f. 23- 

 32), are very good representations of some of the forms of this 

 characteristic species; but the peculiar ornament of the shells 

 of this genus is, I think, not represented. 



In the upper beds of limestone it occurs of great size, some 

 specimens being two inches in length. It is rather scarce in the 

 shell -limestone, and rare in the compact. 



22. ASTARTE ? SoR-evhij. 

 1. A.? Vallisneriana, King. 



The specimens of this shell which I have collected at Whitley 

 are rather more triangular than the figure in the " Perm. Mon.," 

 and very much resemble, both in the general form and ornament 

 of the valves, some young specimens of the recent Venus striatula. 

 The hinge-line is furnished with a deep triangular cartilage-pit, 

 and the character of the superficial ornament is jDreserved on the 

 casts. 



The Astarte Vallisneriana occurs in this district in the com- 



