44 Reports & Proceedings— Mineralogical Society. 



Permo-Carboniferous rocks in all the principal land areas of the 

 southern hemisphere — India, Australia, South Africa, and South 

 America. The obvious method of explaining this remarkable dis- 

 continuous distribution is to assume that there were at one time land 

 connections between these areas, and, indeed some writers have gone 

 so far as to suggest that there formerly existed a great east-and-west 

 continent crossing the site of the present Indian Ocean. To this 

 last continent Suess gave the name Gondwanaland. 



Why should the vegetation of Gondwanaland have been peculiar ? 

 In explanation of this the author made reference to the Talchir rocks 

 of India, the Bacchus Marsh conglomerates of Victoria, the Dwyka 

 conglomerate of South Africa, aud the Orleans conglomerate at the 

 base of the Santa Catharina rocks in Brazil. All these strata, which 

 are in intimate association with the plant-bearing beds, afford 

 indisputable evidence of contemporaneous glacial action in late 

 Palseozoic times. Geologists, therefore, believe that it was tlie 

 secular climatic change accompanying this Permo-Carboniferous 

 glaciation that impressed itself so remarkably upon the vegetation of 

 Gondwanaland, extirpating the older lepidophytic types and giving 

 birth ultimately to the Glossopteris Flora. 



III.— MiNKRALOGICAL SoCIETY. 



Anniversary Meeting, November 6. — Dr. J. "W. Evans in the Chair. 



The following were elected Officers and Members of Council: 

 President, Mr. W. Barlow, P. U.S. ; Yice-Presidents, Professor H. L. 

 Bowman, Mr. A. Hutchinson ; Treasurer, Sir William P. Beale, Bart., 

 K.C., M.P. ; General Secretary, Dr. G. T. Prior, P.R.S. ; Foreign 

 Secretary, Professor W. W. Watts, F.R.S. ; Editor of the Journal, 

 Mr. L. J. Spencer ; Ordinary Members of Council, Mr. T. V. Barker, 

 Mr. G. Barrow, Professor C. G. Cullis, Mr. F. P, Mennell, Mr. H. 

 Collingridge, Mr. T. Crook, Dr. G. F. Herbert Smith, Dr. H. H. 

 Thomas, Mr. H. F. Collins, Mr. J. P. De Castro, Professor H. Hilton, 

 Lieutenant Arthur Russell. 



The following papers were read : — 



Miss E. Smith : On Etched Crystals of Gypsum. Baumhauer 

 conducted experiments on colemannite and calcite to determine 

 whether the phenomenon of etched figures is due to lack of 

 homogeneity or irregularity in the incidence of the dissolving liquid 

 or to lack of homogeneity in the crystal itself. Further experiments 

 now made on cleavage surfaces of gypsum tend on the whole to 

 confirm Baumhauer's conclusion that the second hypothesis is the 

 correct one. 



Dr. G. T. Prior : On the Mesosiderite - Grahamite Group of 

 Meteorites. Analyses of the mesosiderite Hainholz and the 

 grahamite Vaca Muerta show that these meteorites do not diSer 

 materially as regards the amount of felspar, and microscopical 

 examination of other mesosiderites supports the idea that there is no 

 real distinction between them ; the name mesosiderite is therefore 

 proposed for the whole group. The groundmass of these meteorites 

 consists mainly of anorthite and a pyroxene, poor in lime and having 



