OF SOUTHERN INDIA. 315 



The last named locality refers to the latter group, and the specimens from it 

 generally have the ribs thin, and very distinctly tuberculated ; they are also probably 

 slightly less inflated than those from the other group, but there is no important 

 specific distinction between both. 



In Europe T. soahra is common through all the upper cretaceous beds of 

 Germany, France, and the Alpine Gosau deposits. 



2. Trigonia tuberculifera, Stoliczka, PI. XV, Figs. 10-12. 



Trie/, testa late omta, fere aqualiter longa quam alia, valde inceqiiilateraU, 

 tumicla, umbonibus sub-anterioribus, xirominentibus, incurvis instructa, antice leviter 

 convexa, infra valde rotundata, postice breviter prodiLcta et valde angustata, margine 

 areali moderate concavo ; superficie costis 16-18 crassis (equidistantibus, jjcmlo tmdii- 

 latis, ant sub-rectis, tubercidis obtusis coronatis, postice multo teuuioribiis, interdum 

 sub-lmcigatis, ornata ; area moderate profunda, sub-angustata, fere Icevigata. 



This species bears a remarkably close resemblance to the South African 

 T. ventricosa, described by Krauss (Acta nov. Acad. Leop. Car., xiv, pt. ii, p. 456, 

 pi. 49, fig. 2,) from supposed cretaceous beds which have subsequently been 

 referred to the Jurassic period.* I have given (on pi. sv, fig. 9), for the sake of 

 comparison, two views of the African shell, as Krauss's illustrations are not suffi- 

 cient. Our Indian species differs from this only by being of a more regularly 

 rounded triangular shape, less attenuated and produced posteriorly, and possessing a 

 narrower and not so deeply excavated area. The only other shell closely allied, 

 if not identical with the African fossil, is one found by Mr. Wynne in the jm'assic 

 beds of Cutch. I shall have occasion to allude to this at some future date in 

 connection with the examination of the Cutch fossils. 



Locality. — Coonu.m, in a greyish sandstone. 



Formation. — Trichinopoly group. 



b. Group, — CostatcB. 



3. Trigonia indica, Stoliczka, PI. XV, Figs. 14-15. 



T. testa sttb-trigonali, valde iuaquilaterali, sub-tumida, antice rotundata, infra 

 margine convexo, postice gradatim attenuata, moderate producta et ad termina- 

 tionem oblique trmicata, costis 12-13 concentrieis, Immgatis, crassis, antice ad mar- 

 ginem sub-recte terminantibus, sulcis paulo latioribus separatis, ornata; area lata, 

 ad medium angulata, intus aut planulata aut paulo excavata, striis transversalibus 



* I have no doubt that the secondary deposits of South Africa are in part with propriety referred to the Jurassic 

 period, but I am not sure whether they all belong to that formation. Besides the Trigonia ventricosa there is a 

 Remondia, a Grotriania, and a Ptychomya, aud several other shells which have a cretaceous more than a Jurassic 

 aspect. It yet remains to be shown whether Krauss was not correct in his identification of some of the beds with 

 cretaceous deposits, equivalent to the Lower Greensand of Europe. 



4 K 



