﻿24:0 Geological Society : — 



used the spectrum was continuous, with the red line (C) of 

 hydrogen conspicuous, and the F line just visible, and 

 glimpses of the three platinum lines in the green and yellowish- 

 green. When the jar was put into the circuit the hydrogen 

 lines became very diffuse, but the platinum lines came out 

 much more distinctly, and the readings proved their identity. 

 There were no lines which we could identify with oxygen lines. 

 The water became quite brown with the particles thrown 

 off the platinum wires used as electrodes. 



XXYI. Proceedings of Learned Societies. 



GEOLOGICAL SOCIETY. 



[Continued from p. 157.] 



February 7th, 1894.— W. H, Hudleston, Esq., M.A., F.R.S., 

 President, in the Chair. 



Mr. C. J. Alford, F.G.S., in explanation of specimens of auriferous 

 rocks from Mashonaland exhibited by him, stated that several of 

 them were vein-quartz occurring as segregations in the slates, 

 generally forming veins between the cleavage-planes. Another 

 specimen was a mass of chromate of lead, with pyromorphite and 

 other lead minerals, occurring in masses in decomposed and dislo- 

 cated talcose slate in the Penhalonga Mine near Umtali, and probably 

 resulting from the alteration of masses of galena by weathering, 

 as a broken vein of galena was found in close proximity. This 

 Crocoisite was supposed to be a somewhat rare mineral, but he 

 had found it and also the native red oxide, Minium, in several places 

 in South Africa. The most interesting specimen was, however, a 

 mass of Diorite showing visible gold throughout the rock, an assay 

 of which gave upwards of 130 ounces of gold per ton. From 

 information obtained from the prospector who made the discovery, 

 he gathered that the deposit was a dyke of Diorite running for a 

 considerable distance, about 8 feet in width, flanked on one side 

 by granite and on the other by slates. There were extensive 

 ancient workings extending to a depth of about 60 feet, and the 

 prospecting shafts had not gone much below that depth, so not 

 much information was obtainable at present. The Diorite showed 

 a development of Epidote, but little or no quartz; and the gold 

 appeared to enter in an extraordinary manner into all of the com- 

 posing minerals. Mr. Alford hoped, after his next visit to Mashona- 

 land, to be in a position to lay before the Society more definite 

 information regarding these interesting rocks. 



The following communications were read : — 

 1. ' On some cases of the Conversion of Compact Greenstones 

 into Schists.' By Prof. T. G. Bonney, D.Sc, LL.D., F.E.S., F.G.S. 

 By the path leading from the Bernina Hospice to the Griim Alp 



