•46 Reports and Proceedings — Minemlogieal Society. 



of Tasmania. The decapods have now usurped the present shores 

 and the shallow seas. 



Dr. Peach further showed that all the above families existed in 

 the earliest Carboniferous times, and that they must have branched 

 off from a nebalid stem at a much earlier geological date. 



MiNERALOGiCAL SooiETY OF LoNDON, November 15th. 



Professor H. A. Miers, F.H.S., President, in the chair. Dr. J. W. 

 Evans described two new forms of quartz-wedge, by means of which 

 approximate quantitative estimations can be readily made of the 

 double refraction of minerals in small grains or in rock-sections. 

 Mr. J. Currie contributed a note on some new localities in Scotland 

 and the Faroes of gyrolite and tobermorite, and Mr. C. E. Lindsey 

 one on the occurrence of microscopic crystals of brookite with 

 anatase in the Cleveland ironstone. Mr. R. H. Solly exhibited and 

 described various minerals from the Lengenbach quarry, Binnenthal. 

 Three of these were new, viz. marrite and bowmanite, of which 

 the chemical composition has not yet been determined, and lengen- 

 bachite, which has been shown by Dr. Hutchinson to be a sulph- 

 arsenite of lead containing some copper and antimony, and having 

 a specific gravity of 5-8. Marrite occurs in small lead-grey crystals 

 resembling modified cubes, and lengenbachite in thin lead-grey 

 blade-shaped crystals, some as long as 40 mm., showing a highly 

 perfect cleavage. Marrite crystallises in the oblique system with 

 a : 6 : c = 0-57634 : 1 : 047389, and /3 = 88° 45', while lengenbachite 

 is probably anorthic. Bowmanite occurs in small honey-yellow 

 rhombohedral crystals with 111 : 100 = 53° 50'. It has a highly 

 perfect cleavage parallel to 100, and a specific gravity of about 3-2. 

 The author also described twinned crystals of seligmannite dispersed 

 over large crystals of dufrenoysite and baumhauerite, and curious 

 highly modified crystals of blende showing a thin metallic lead-grey 

 coating. Mr. H. L. Bowman described crystals of a mineral from 

 Cornwall which had been sent to him for determination by Mr. F. H. 

 Butler. They were found to be bertrandite, a mineral new to the 

 British Isles. Mr. G. F. Herbert Smith exhibited a slightly modified 

 form of the hand refi-actometer which he had previously described. 

 Mr. H. Hill contributed notes on some applications of the gnoraonio 

 projection to crystallography, and on the construction of crystallo- 

 graphic projections. 



Manchester University Geologists' Association. 



A meeting was held in the Geological Lecture Theatre of the 

 Owens College, Manchester, on December 8th, at which it was 

 resolved to estai)lish a Manchester University Geologists' Association. 

 The object of the Association is to afford a centre of social reunion 

 for the discussion of geological subjects. Past and present students 

 of the University are eligible for membership, also others 

 interested in geology who may be recommended by the Committee. 



