186 Reports and Proceedings. 



the Commission on the London Water Supply to furnish this city with 

 water from deep wells, and indicated the disastrous effects that would 

 be produced over a great extent of country if this scheme were to be 

 adopted. The address was prefaced by some obituary notices of 

 Tellows and Foreign Members deceased during the past year, includ- 

 ing Sii' Charles Lyell, Mr, Poulett Scrope, Sir Wm. Logan, M. G. P. 

 Deshayes, Mr. W. J. Henwood, Mr. W. Sanders, Archdeacon Hony, 

 Sir Edward Eyan, and others. 



The Eallot for the Council and Officers was taken, and the fol- 

 lowing were duly elected for the ensuing year : — President : Prof. 

 P. Martin Duncan, M.B., F.R.S. Vice- Presidents : Sir P. de M. Grey 

 Egerton, Bart., M.P., P.R.S; R. A. C. Godwin-Austen, Esq., E.R.S. ; 

 J. W. Hulke, Esq., E.R.S. ; Prof. A. C. Ramsay, LL.D., E.R.S. 

 Secretaries: David Eorbes, Esq., E.R.S. ; Rev. T. Wiltshire, M.A. 

 Foreign Secretary/ : Warington W. Smyth, Esq., M.A., E.R.S. 

 Treasurer : J. Gwyn Jeffreys, LL.D., E.R.S. Council: H. Bauerman, 

 Esq. ; Rev. T. G. Bonney, M.A. ; W. Carruthers, Esq., E.R.S. ; 

 Erederick Drew, Esq.; Prof. P. Martin Duncan, E.R.S.; SirP.de 

 M. Grey Egerton, Bart., M.P., E.R.S. ; R. Etheridge, Esq, E.R.S.; 

 John Evans, Esq., E.R.S. ; David Eorbes, Esq , E.R.S. ; R. A. C. 

 Godwin- Austen, Esq., E.R.S.; Henry Hicks, Esq.; J. W. Hulke, 

 Esq., E.R.S.; J. Gwyn Jeffreys, LL.D., E.R.S.; Prof. T. Rupert 

 Jones, E.R.S. ; J. W. Judd, Esq. ; Prof. J. Morris ; Prof. A. C. 

 Ramsay, LL.D., E.R.S. ; Samuel Sharp, Esq., E.S.A. ; Warington 

 W. Smyth, Esq., M.A., E R.S. ; Admiral T. A. B. Spratt, C.B., 

 E.R.S. ; W. Whitaker, Esq., B.A. ; Rev. T. Wiltshire, M.A., E.L.S. ; 

 Henry Woodward, Esq., E.R.S. 



TIL— Eebruary 23, 1876.— Prof. P. Martin Duncan, M.B., E.R.S., 



President, in the Chair. The following communications were read: — 



1. '^On the Greenstones of Western Cornwall." By John Arthur 

 Phillips, Esq., E.G.S., E.C.S. 



In this paper the author brought forward evidence to show that 

 the so-called ''greenstones" of Penzance really belong chiefly to the 

 following three classes : — 



a. Gabbros or Dolerites, in which the originally constituent minerals 

 are either to a great extent unchanged, or, sometimes, almost entirely 

 represented by pseudomorphic forms. 



h. Killas, or ordinary clay-slates. 



c. Highly basic homblendic rocks, exhibiting a tendency to break 

 into thin plates ; these under the microscope present the appearance 

 of metamorphosed slates. 



Slaty rocks of a character intermediate between h and e also occur. 



In the Cape Cornwall district the " greenstones " are chiefly 

 homblendic slates, sometimes with veins or bands of garnet, mag- 

 netite, or axinite. The rocks near the Gurnard's Head are almost 

 identical with those of Mount's Bay. The crystalline pyroxenic 

 rocks and metamorphic slates of the St. Ives district exactly re- 

 semble those of Penzance. The greenstones between St. Erth and 

 St. Stephen's are probably altered ash-beds or hardened homblendic 

 slates; unlike the homblendic and augitic rocks of the other dis- 



