ASTARTE. 107 



Distribution. — Zone of Belemnites lateralis: in the Speeton Clay of Speeton 

 and the Claxby Ironstone of Benni worth Haven. 



Astakte, sp. Plate XIV, fig. 21. 



Description. — Shell oval, moderately convex, slightly inequilateral, length 

 greater than height. Antero-dorsal margin concave. Anterior margin rounded, 

 passing gradually into the curved ventral margin. Postero-dorsal margin convex, 

 forming a rounded angle with the posterior margin. Umbo pointed. 



Ornamentation consists of about 15 strong, rounded, concentric ribs separated 

 by rounded furrows of greater breadth. Fine concentric ridges occur on both ribs 

 and furrows. The ribs cut the postero-dorsal margin at a large angle ; they are 

 more widely separated on the dorsal than on the ventral half of the valve. 



Length 12'5 mm. ; height, 11*2 mm. 



Rem avis. — This species is known by a single right valve only. The ornamenta- 

 tion is somewhat similar to that of A. senecta, but the shell is more oval and less 

 inequilateral, also the ribs are more numerous and form a larger angle with the 

 postero-dorsal margin. 



Distribution. — Speeton Clay of Speeton. 



Astarte cantabeigiensis, sp. nov. Plate XIV, figs. 22 a, b, 23 a, b, 24. 



1883. Astarte subdentata, W. Keeping. Foss., etc., Neoc. Upware and Brick- 

 hill, p. 122, pi. vi, fig. 11 {non 

 Komer) . 



Description.— Shell subquadrate, longer than high, very inequilateral, moderately 

 inflated, with the greatest convexity between the umbo and the postero-ventral 

 angle. Postero-dorsal margin long, slightly convex, forming an obtuse angle with 

 the truncated posterior margin, and a blunt angle where it joins the slightly convex 

 ventral margin. Anterior margin rounded. Lunule deep, ovate, distinctly limited. 

 Escutcheon deep, with a sharp edge. 



Ornamentation consists of strong concentric ribs bearing finer ribs. 



Measurements : 



(1) (2) (3) (4) (5) 



Length . 17'5 15 15 14 14 



Height . 16 13-5 13 125 12 



(1-8) Lower Greeusand, Upware. 



(6) 



(<) 



(8) 



L3-5 



13 



12 nun 



12-5 



11-5 



10-5 „ 



