Reports & Proceedings — Mineralogical Society. 135 



8. Permian of Dttkham. — Dr. Woolacott's paper, printed in abstract 

 only by the Geological Society of London in 1911, has now appeared 

 in full in the Proc. Univ. Durham Phil. Soc, vol. iv (5), 1912. It 

 runs to seventy pages, is well illustrated, and issued at half a crown, 

 so should be useful to many geologists. Attention may be directed to 

 several excellent photographs showing weathering of the local rocks. 



9. Thk Hamada CouNTRr. — Under this title we welcome a short 

 paper on a part of Sinai by G. W. Murray, the son of our late 

 colleague, G. R. M. Murray, of the British Museum. The district 

 contains the Sinaitic minerals, copper, turquoise, manganese, iron 

 and petroleum, and a good series of Carboniferous rocks. It is 

 also much broken by a series of titanic faults, one of which has 

 a throw of 1,320 metres. The paper is illustrated by photographs 

 and a well-printed coloured geological map. It appeared in the 

 Cairo Scientific Journal, vol. vi (No. 74), pp. 264-73, November, 1912. 

 The paper is frankly of a general nature, but contf^ins many valuable 

 geological notes. 



10. DtJDDON Estuary. — Those interested in J. F. N. Green's paper 

 on this area which was read before the Geological Society of London 

 on March 27, 1912, and published by the Society in the Abstract of 

 Proceedings, 1911-12, p. 71, will be glad to hear that the whole 

 paper has now been privately printed by Mr. Green and is available 

 for reading and consideration. 



11. Microscopical Petrography. — Dr. F, E. Wright contributes 

 to the Journal of Geology for September-October, 1912, a paper on 

 microscopical petrography from the quantitative viewpoint, in which 

 he emphasizes the fact, not always realized by petrographers, that 

 the quality of the quantitative work is far more important than the 

 quantity of the qualitative work, and reproduces the main features 

 of his discussion and description of tlie most refined methods of 

 microscopic research published by the Carnegie Institution of 

 Washington. 



I. — Mineralogical Society. 



January 21, 1913. — Dr. A. E. H. Tutton, F.R.S., President, in 

 the Chair. 



T. V. Barker and J. E. Marsh : Optical Activity and Enantio- 

 morphism ,of Molecular and Crystal Structure. The general nature 

 of enantiomorphous structures accompanying optical activity in the 

 liquid and crystalline conditions was discussed, and it was [)ointed out 

 that, since the optical activity observed in crystals of six substances, 

 including epsomite and sodium chlorate, cannot be referred to the 

 crystal structure, it must be due to an enantiomorphous configuration 

 of the atoms within the molecule. Suitable enantiomorphous con- 

 figurations have been deduced on chemical grounds, the constitution 

 of the compounds being based on a modification of Werner's theory of 



