Minutes of Proceedings. 
xxix 
respective ranges of velocity being *32 and -55 miles an hour, which are 
greater than one would have expected to find. 
" South African Perisporiaceae. V : Notes on an Interesting Collection 
from Natal." Miss Ethel M. Doidge. 
A number of leaf fungi are described from jSTatal, chiefly belonging to 
the genus Meliola, and including hitherto undescribed species. 
" Fusion of Karroo G-rits in Contact with Dolerite Intrusions." By 
Andrew Young. 
Certain unusual contact alterations occurring in the Heilbron district 
were described. Dolerite intrusions have apparently fused the Karroo 
sandstone or grit to a dark glass resembling pitchstone. The contacts are 
sharply defined, and the vitrification extends to a distance of several yards 
from the actual contact plane. The results of a detailed petrological 
examination of the dolerite, the glass, and the sandstone were described. 
The dolerite presents no abnormal features. The sandstone contains much 
soda felspar. The glass on analysis yields about 7 per cent, of soda and 
about 5 per cent, of combined water. The glass might thus be called 
a pitchstone. Microscopic examination of the glass shows the presence 
of microlites of cordierite, magnetite, and also a fibrous mineral with 
physical properties suggestive of an amphibole. These microlites seem to be 
practically identical with those described by Harker and Clough as occurring 
under somewhat similar circumstances in the island of Soay near Skye. 
" On Hyalite." By J. S. v. d. Lingen and A. E. E. Walker. 
The points of resemblance between hyalite and liquid spherulites are 
noted. The truth of the statement that liquid spherulites and — under 
certain conditions — hyalite, give uniaxial figures when examined in con- 
vergent polarised light is questioned. 
" On Anatase." By J. S. v. d. Lingen and A. R. E. Walker. 
The authors exhibited a Laue radiograph of Anatase which shows that, 
according to the usual interpretation of such a photograph, the mineral 
possesses full tetragonal symmetry. 
Herbert Smith and W. von Bonde have, independently, suggested that 
possibly it did not possess the full degree of symmetry usually assigned 
to it ; in both cases this suggestion was based on a study of the external 
crystal form of the mineral. 
" On Radioactive and Other Minerals Associated with Fossil Wood from 
the Beaufort Series." By A. R. E. Wali^er. 
A description is given of torbernite and a mineral allied to uranocircite 
occurring, associated with calcite and barytes, encrusting and impregnating 
fossil wood from beds of Lower Beaufort age on the farm Quaggasfontein. 
" On Tantalite Crystals from Namaqualand." By A. R. E. Walker. 
A description is given of a number of crystals obtained from a tantalite 
prospect at Jakals Water, Namaqualand. 
