46 FAUNA OF BALUOHISTIN. 



the other hand, show an average height of not less than 40 mm. In accordance 

 with the larger size the ribs are much broader and flatter and the interstices generally 

 narrower thfin in the Sind specimens. It must also be remarked, that the tri- 

 partition of the ribs is much more distinct in all the Baluchistan specimens than in 

 the type from Sind. 



Now the question arises, are the differences just mentioned, suflacient to justify 

 a specific separation of the two types or not ? Erom my point of view I contend 

 that a separation of forms which otherwise agree, on features as detailed above, 

 would be going too far. I am inclined to think the different features of the two 

 types represent either local varieties, or perhaps forms belonging to two slightly 

 difl'erent geological horizons. The latter question can only be settled when the 

 whole of the fauna of the upper cretaceous systems of Sind and Baluchistan is 

 known, but it may already be remarked, that notwithstanding a great similarity of 

 the upper cretaceous fautia of Sind and Baluchistan, the former contains species 

 which are not yet known from Balucliistdn, while the latter has yielded forms which 

 are certainly not known in Sind. 



The nearest relation to Cardita beaumonti, d'Archiac, appears to be Cardita 

 inflata, Leymerie, from the etage Garumnien. Unfortunately M. Leymerie's figure 

 of that species is too defective, and his description too short, to allow of more than 

 attention being drawn to the close similarity between the two forms. It is quite 

 possible that on actual comparison, the ilwo species will be found identical, in which 

 case the specific name beaumonti, d'Archiac, ought to receive the priority. 



Cardita (Venericardia) stibcomplanata, d'Archiac. PI. XII. fig. 3-3a. 



1853. Cardita subeomplanata, d'Archiac and Haime, Description des Anim. foss da Groupe numm. de 

 I'Inde, p. 253, pi. XXI, fig. 11, o, b. 



Dimensions. 



Length 14 mm. 



Height 15 „ 



Thickness 8 „ (?) 



The small shell is equivalve, suborbicular in shape, and not very inequilateral. 

 The beaks are slightly inflated, depressed, and situated close to the anterior margin. 

 The anterior, central, and posterior margins form nearly a complete circle ; but 

 there is a distinct angle at the point where the ventral and posterior margins join. 

 Valves slightly inflated and compressed. The ornamentation consists of 20 radiat- 

 ing ribs, which are slightly curved in the posterior direction ; the ribs are angular, 

 of the same thickness and as broad as their interstices ; they are crossed by numer- 

 ous, regular, closely set, concentric striae of growth, which render them foliaceous. 

 Lunula well defined, heart-shaped and rather broad, but not deep. 



Locality and stratigraphical position. — Des valley. 



Remarhs. — The Baluchistdn forms agree so well with d'Archiac's Cardita sttb- 

 complanata from Sind, that there can be no doubt as to their identity ; it seems that 



