Obituary — Robert Etheridge. 289 



and oriented parallel to the banding. The slight amount of rotation 

 of crystals possible in the compacted part of the mesh would not be 

 sufficient to orient them in any particular way. The action would, 

 as a whole, give rise to bands showing flow-structure, therefore, 

 and exhibiting the moderate contrast between bands that is normal 

 in banded gabbro. The occasional ultra-basic bands of extreme 

 contrast could also be developed as a further result, for in the 

 larger lenses of liquid crystal sorting would occur under conditions 

 particularly favourable to the production of monomineralic types. 



Though apparently not himself a strong advocate of crystallization 

 differentiation, Mr. Read appears to have some apprehension that 

 the credit for originating certain ideas in that connexion might leak 

 out of the Tight Little Islazid. He therefore points out that Darwin 

 postulated crystal-settling seventy years ago, and in two places 

 that Barrow postulated mechanical straining thirty years ago. 

 Though Darwin needs no eulogy of mine or Mr. Read's, I too have 

 pointed out Darwin's origination of the idea of crystal-settling,^ 

 and thoLigh T have not referrt'd directly to Barrow'? work. I have 

 referred to Harker's discussion of it and similar work.^ If 1 ma v be 

 permitted, I would like to point out to Mr. Read that the 

 assumption of immiscibility also dates back to Darwin's time, 

 and that it is still an assumption — a sylph, if he prefers the term. 



N. L. BowEN. 



Kingston, Canada. 



February 27, 1920. 



OBITUARY. 



Robert Etheridge (1847- 1920). 



Mr. Robert Etheridge, the son of the distinguished geologist and 

 palaeontologist of that name, died after a short attack of pneumonia 

 at Colo Vale, near Sydney, on January 4, in his 74:th year. Etheridge 

 early took up geological work in Australia, as a member of the first 

 Greological Survey of Victoria, under the direction of A. R. C. Selwyn, 

 in the middle sixties. The survey having been disbanded as the 

 result of a ]3olitical crisis, young Etheridge returned home and was 

 appointed paleeontologist to the Geological Survey of Scotland, his 

 father being then palaeontologist to the English Survey. When the 

 natural history collections of the nation were removed from 

 Bloomsbury to the new Natural History Museum in the Cromwell 

 Road, the two Etheridges were brought on to the staff of the 

 Geological Department, where the memory still remains of the 

 vigorous actions and language of " R. E. junior ". The chief piece 

 of j)al8eontological work accomplished by Etheridge while in this 



^ N. L. Bowen, "Crystallization Differentiation in Silicate Liquids": 

 A7n. Journ. Sci., vol. xxxix, 1915, p. 175. 



■"^ "Later Stages of the Evolution of the Igneous Rocks " : Journ. Geo!., 

 Suppl. to vol. xxiii, 1915, p. 14. 



