8 Mr. R. B. Newton on some 



Glossopteris inclica (Compt. Rendus, 1908, vol. cxlvi. pp. 502- 

 504- & vol. cxlvii. pp. 818, 819), a species of fern known from 

 the late Palaeozoic deposits of South Africa, India, Australia, 

 Tasmania, Falkland Islands, and South America (Argentina). 



The discovery of such an assemblage of fossils was a 

 great advance on our previous knowledge of Madagascan 

 geology, because it proved, on the one hand, relationships 

 with the Karoo beds of Southern Africa, and, on the other, 

 with the Gondwana deposits of India and other geologically 

 related regions. With regard to the molluscan remains 

 brought home by Mr. Dixon from this northern district 

 of the island, it may be mentioned that neither a Planor In- 

 form shell of so ancient an horizon nor Naiadites have yet 

 been recorded from Africa or India. The Karoo formation 

 of Africa, and especially the Beaufort-beds division, has 

 yielded freshwater pelecypods belonging to the genera 

 Palaomutela and Palceanodonta of Professor Amalitzky, which, 

 that author some years since pointed out, resembled almost 

 species for species a fauna characteristic of the upper part 

 of the Russian Permian formation, and so he considered 

 those distant deposits as homotaxially equivalent (Quart. 

 Journ. Geol. Soc. 1895, vol. li. pp. 337-351, pis. xii., xiii.). 



In the latest work on South African geology we find that 

 Dr. A. W. Rogers acknowledges Amalitzky's work and 

 brackets the Beaufort series with the Permian of Europe 

 (A. "W. Rogers and A. L. Du Toit, 'An Introduction to the 

 Geology of Cape Colony/ 1909, 2nd edition, pp, 231, 243). 

 No similar bivalve mollusca are known irom the Gondwana 

 beds of India, and it is chiefly from the facies of the 

 Glossopteris flora characterizing those deposits that a 

 homotaxial relationship with the African Karoo has been 

 demonstrated. 



It would seem, therefore, that in future correlation schemes 

 connected with the geological history of Madagascar we 

 have to recognize not only Captain Colcanap's and Professor 

 Boule's important discoveries as to the presence of Upper 

 Palaeozoic deposits in that island, but also to include the 

 valuable fish and molluscan remains collected by Mr. Dixon, 

 which add a new interest to the paleeontological features of 

 those beds. 



Description of the Mollusca. 



Gastropoda. 



Plunorbis dixoni, sp. n. (PI. I. figs. 6, 7.) 



Shell small, discoidal, plano-convex, and furnished with a 



smooth peripheral carination ; outer whorl wide and equal 



