Geological Society. L vo 
The chief ingredients, so to speak, in Nordmann’s theories are 
Hertzian waves (mainly from the sun), cathode rays excited by 
these waves (Ebert and Wiedemann), and gaseous lavers of 
critical density for maximum illumination (J.J. Thomson). There 
is also occasional use of the ‘‘ Maxwell-Bartoli” pressure of light 
as opposing gravitation. Abstracts of theories are seldom satis- 
factory—at least to the propounder ; and the reader who wishes 
particulars must be referred to the original Thesis. ©. C. 



X. Proceedings of Learned Societies. 
GEOLOGICAL SOCIETY. 
[Continued from vol. vi. p. 723. ] 
November 18th, 1903.—Sir Archibald Geikie, D.Sc., F.R.S., 
Vice-President, in the Chair. 
HE following communications were read :— 
1. ‘Notes on some Upper Jurassic Ammonites, with Special 
reference to Specimens in the University Museum, Oxford.’ By 
Miss Maud Healey. 
2. ‘On the Occurrence of Hdestus in the Coal-Measures of Britain.’ 
By Edwin Tulley Newton, Esq., F.R.S., V.P.G.S. 
December 2nd.—Sir Archibald Geikie, D.C.L., D.Sc., Sec.R.S., 
Vice-President, in the Chair. 
The following communications were read :— 
1. ‘ Notes on the Garnet-bearing and Associated Rocks of the 
Borrowdale Volcanic Series.’ By the late Edward Eaton Walker, 
Esq., B.A., B.Sc. 
The first portion of the paper is occupied with an account of 
various intrusive rocks. A detailed description of sills and dykes 
of garnet-bearing rocks in the Langstrath Valley is given; and 
similar rocks are described, occurring as dykes and sills around the 
Eskdale granite and the Buttermere granophyre, and also in the 
Armboth-Helvellyn area. These rocks vary in degree of acidity. 
They consist of diabase, porphyrite, and granophyre. Evidence of 
their characters being dependent upon differentiation accompanied 
by some absorption is offered. They appear to be related to the 
Eskdale and Buttermere masses of intrusive rocks. 
The volcanic rocks are next considered. Garnets are found 
in the Falcon-Crag Group, in a group of rocks below the great 
banded ashes and breccias of the Scawfell Group, and in the rocks 
of the Scawfell Group itself; but do not seem to occur, except as the 
result of contact-metamorphism, in the Eycott Group. The most 
interesting garnetiferous volcanic rocks are those which occur 
below the Scawfell ashes and breccias. These rocks often have 
a streaky structure which exhibits four distinct types: resulting 
from (a) infiltration along planes of weakness, (b) lamination of 
ash, (c) flow of igneous material, and (d) dynamic action on 
included fragments. The rocks are not intrusive, but consist of lavas 
and ashes, often exhibiting alternating bands of rhyolite and andesite. 
The banded ashes of the Scawfell Group also contain garnets. 
