DEPARTMENT OF MINERALOGY. 141 



The minerals of the Geological Society's collection have been 

 all provided with permanent labels and incorporated in the General 

 Collection. 



Papers relating to the large round table of antique marbles 

 have been placed together in a drawer specially constructed under 

 the table, and a label has been printed and framed for the table. 



A scheme has been considered for a complete and detailed topo- 

 graphical index of all the localities represented in the mineral 

 collection. 



An alphabetical list of rock names represented in the collections 

 has been compiled, and a copy has been placed for public use in 

 the Gallery. 



The topographical index of the rock-collections has been brought 

 up to date. 



Letters received during 1918 have been arranged for reference. 



III. — Prepartion . 



155 micro-sections of minerals, meteorites, and rocks have been 

 prepared ; three meteorites have been cut ; and six pieces of 

 meteoric iron have been polished for etching. 



I V . — Investuiat'wii . 



A crystallographical inv(\stigation of the series of crystals of 

 lead and copper minerals from Red Gill, Cumberland, and Leadhills, 

 Lanarkshire, in the Trechmann Collection has been in progress, and 

 many crystals of linarite and caledonite have been measured. 



The crystalline form and physical characters of the new Spanish 

 mineral villamaninite have been determined, and a description has 

 been written. 



The crystallographic constants of other apparently new minerals 

 have been determined, viz., a blue copper-zinc phosphate from 

 Rhodesia and a uranium-lead silicate from the Belgian Congo. 



Artificially-produced crystals of tin arsenide have been measured 

 and described : and in this connection a study has been made of the 

 question of curvature in crystals, a general account of which has 

 been prepared. 



New crystal-forms have been determined on calcite, pyrites, and 

 e))idote, and these have been described and figured. 



Specimens collected and presented by F. N. Ashcroft from 

 Derbyshire, Cumberland, and Renfrewshire have been examined and 

 determined. 



Among other species which have been examined for purposes of 

 identification or other reasons may be mentioned stibnite and 

 bournonite from Spain, scorodite from Cornwall, tarbuttite and 

 hopoite from Rhodesia, allophane from British Columbia, and 

 fibrolite from Scotland. 



The investigation of the metamorphic rocks represented in the 

 coll(>ctions of the " Terra Nova " Antarctic Expedition has been in 



