140 Reports and Proceedings — Mineralogical Society. 



sand, and clay. These ancient valleys all proved tbat when they 

 were scooped out by swift rivers the land was much higher than 

 it is now. Mr. Cadell went on to discuss this conclusion, and he 

 showed that if the gradient of the ancient Forth was 25 feet per 

 mile, the glen must have been 1,000 feet deep at the Forth Bridge, 

 and the North Sea bed was a great plain. He exhibited interesting 

 panoramic sketches he had painted, showing what he imagined was 

 the scenery of the Forth Valley at that period where the islands 

 of the Firth were the tops of rocky pinnacles, and hairy elephants, 

 bears, and wolves roamed through the forests of the pre- Glacial 

 continent, before Britain was an island. 



III. — Mineralogical Society. 



January olst, 1905. — Professor H. A. Miers, F.R.S., President, in 



the Chair. 

 Mr. H. H. Thomas gave a detailed account of the crystallographic, 

 optical, and chemical characters of epidote found in a vein in gneiss, 

 near Barrisdale, Inverness-shire. A chemical analysis made by 

 Dr. Pollard showed that the mineral contained a very low percentage 

 of ferric oxide (6-81). In this respect it was similar to epidotes from 

 Huntington, Mass., and the Zillerthal, and like them showed corre- 

 spondingly low refractive and double refractive power and large optic 

 axial angle, as compared with epidotes containing higher percentages 

 of iron. — Mr. T. V. Barker communicated a preliminary note on the 

 regular growth of crystals of one substance upon those of another. 

 The observations of previous investigators were in general confirmed 

 with regard to the growths of K I, K Br, K C I, and Na Noj upon 

 mica, and of Na N03 upon calcite. In all cases a clean surface is 

 necessary. Attempts to get a regular deposition of Na N03 upon 

 other rhombohedral carbonates of the calcite group and upon 

 dolomite were without any positive result, although the rhombohedral 

 angle of some of them is much nearer to that of Na N03 than is that 

 of calcite. The topic axes, however, are in order of magnitude as 

 follows : Na N03, calcite, rhodochrosite, dolomite, chalybite, so that 

 if the regular growth depend on the fitting together of similar 

 structures the experiments point to the usefulness of the conception 

 of topic axes. The author is continuing his observations. — Mr. K. A. K. 

 Hallowes described an apparatus fur determining the density of 

 small grains. The method is by hydrostatic weighing, and the 

 grain is held under water (or preferably alcohol) in a spring-clamp, 

 made of brass wire and two cover-glasses, which is suspended from 

 the beam of the balance by a fine hair. — Professor H. A. Miers 

 exhibited a specimen of massive danalite from Wheal Maudlin, 

 a new locality for this mineral in Cornwall, and also a crystal of 

 barium-radium bromide, the crystallographic characters of which he 

 also described. Mr. Arthur Russell exhibited a specimen of 

 phenacite and one of aurichalcite from Cornish localities, and 

 Mr. H. F. Collins specimens of sulphide of lead and oxide of zinc 

 artificially produced in furnaces at Laurium. 



