356 PKOCEEMNGS OF THE GEOLOGICAL SOCIETY. [March 8, 



IV. CoTTALDiA Cakteki, spcc. nov. The test is circular in outline, 

 much compressed above and below, and tumid at the sides. The 

 tubercles are of the same size, both on the ambulacral spaces and 

 interambulacral areas. There are two rows of tubercles in the am- 

 bulacral spaces, and from six to eight in the interambulacral areas ; 

 the tubercles are arranged moderately horizontally, are surrounded 

 by a scrobicular circle, which is ridged and faintly granular. The 

 generative pores are five in number. The pores of the poriferous 

 zones are in single pairs throughout. The peristome is at the bottom 

 of a rather deep cavity. Breadth of test 1^ inch ; height ^ inch. 

 The size, compressed shape, and the disposition of the tubercles dis- 

 tinguish this species from that nearest to it, the C. BenetticB, Koenig, 

 sp., which is so characteristic of the British and Prench Upper 

 Greensand. C. Carteri is clearly the representative of its close ally. 



V. EcHiKOBKissTJS siTBaTTADBATus, D'Orb., sp. This Neocomian 

 type is represented by a variety at Bagh, of which there are several 

 specimens in various grades of growth. The variety has all the 

 minute details of the specific form, but the posterior margin is not 

 incurved or emarginate ; it is faintly out of the curve in the convex 

 direction, but not more. This variety is so like the type in its other 

 essentials, that it clearly led to the error of giving a Neocomian age 

 to the beds at Bagh. The specimens are mineralized, like the rest 

 of the collection ; and although there is of course a suspicion, of their 

 being " derived," still there is quite as mvich to be said to the 

 contrary. 



7. On the Affinity and Identity of the Species with those of other 

 and remote Cretaceous Strata, and on the Correlation of the Arabian 

 and Bagh Beds with the typical European Series. — It is hardly neces- 

 sary to observe that the close affinity of the Bagh and South-eastern 

 Arabian fossils, the position of the strata with regard to the great 

 south-west fault, and their conformability to an unfossiliferous sand- 

 stone render the parallelism of the two deposits tolerably evident. 

 They present a remarkable assemblage of Echinodermata and some 

 other fossils very characteristic of the European Upper Greensand 

 and Lower Chalk. Most of the species have a wide range, both ver- 

 tically and horizontally ; some are restricted in their bathymetrical 

 difirision in certain European strata, but are not so in others ; and it 

 is one of the singularities of the collections that they should com- 

 prise many of the European Echinodermata* which have this wide 

 range and a tendency to vary also. Mr. Darwin's generalization, 

 that largely diffiised species vary greatly, obtains much confirmation 

 from the study of collections like these. 



All the species are fairly Cretaceous, and there is no admixture of 



* Much credit is due to the philosophic investigations of Messrs. Cotteau and 

 Triger (Echinides de la Sarthe, 1861), who have so faithfully recorded the nu- 

 merous Tarieties of many species which were considered yery typical and stable 

 in the French Cenomanien. The determination of the varieties of some of the 

 species which occur in the Asiatic strata has been greatly facilitated by their 

 researches, and by considering and acting upon the latitude which can be fairly 

 given to variation in Europe. 



