^32 EEV. J. F. BIAKE ON THE 



different from tliose occurring in the Osmington Oolite, they are 

 figured for greater certainty. These are depressed ; umbones nearly 

 median. There are two or three deep concentric furrows, and three, 

 five, or more well-marked ribs between. The hinge shows the same 

 arrangement of alternate lateral teeth as noted above. 



ASTAKTE S^MANNI, Dc Loriol. PI. X. fig. 5. 



This is perfectly characteristic, and an important fossil for corre- 

 lation. In the Swindon Sands of Swindon. 



CYPErNTA ELONGATA, SpCC. UOV. PI. IX. figS. 14, 14a. 



Breadth a little more than |- the length ; thickness of the double 

 valves |- the length. Beaks a little anterior, rather prominent, 

 anterior border subtruncately rounded ; posterior side with a very 

 feebly marked-off slope, which makes the border subtruncate ; 

 pallia! border gently convex. Surface with concentric lines of 

 growth. The ligament is often preserved in those behind the um- 

 bones. This differs from (7. impUcata by being more elongated, 

 and hence less trigonal. Its thickness is also less. 



Abundant in the Trigonia-heds of Swindon, the creamy limestones 

 of Coney Hill, and in the Plinty series and upper part of the Port- 

 land Sand in the Isle of Portland. 



Cypkina implicata, De Loriol. PI. IX. figs. 13, 13a. 



Our specimens agree perfectly with the type, and occur chiefly on 

 a lower horizon than the last, namely in the rubbly limestones of 

 Aylesbury, and in lower beds in the Portland Sand on the coast. 



Cyprina swindonensis, spec. nov. PI. X. fig. 2. 



Breadth not quite two thirds the length ; valves not very inflated ; 

 beaks |- anterior, not prominent ; anterior border rounded, posterior 

 border obliquely truncate, the hinge-line sloping downwards, and a , 

 broad ill-defined area extending from the umbo to the posterior 

 side; pallial margin greatly and uniformly convex. Shell with 

 rough concentric lines of growth. This has a resemblance to C. 

 Loweana, Lycett ; but its pallial border is not so convex, and the 

 posterior region is more markedly truncate. 



Common in Swindon Sands, Swindon. 



UNiCAEDirM ciEcuLAEE, D'Orbiguy. PL X. fig. 1. 



D'Orbigny's short description of a Unicardium from Portland 

 rocks, in his ' Prodrome,' '^ espece circulaire, renflee, plus courte sur la 

 region anale, ridee concentriquement," answers very fairly for our 

 species, which Mr. Damon appears to have found also at Portland. 

 In point of fact its chief feature is its circular outline ; but it is not 

 very inflated. It is not uncommon in the rubbly limestones of 

 Quainton, Coney Hill, &c. 



Caedifm ? cALCAEEiJM, spcc. nov. PI. IX. fig. 15. 



. This is a rather obscure species allied to C, Dufrenoycum, 



Buvignier. 



