236 Reports and Proceedings — 



this as the exception rather than the rule. That peridote occurs as 

 an original constituent both in Carboniferous and Tertiary basalts is 

 a view held by Allport and nearly all petrograpbers, and the effort 

 on the part of the authors to prove that it is to a very great extent 

 a secondary product, pseudomorphous after augite, looks very much 

 like an attempt to turn the tables on their adversaries. They are 

 particularly careful, it should be observed, to exclude the " extra 

 mundane " peridotes, seeing that, since no hydrous minerals have 

 yet been found in meteorites, nor any certain trace of water, the 

 supposition that meteoric peridote is a methylosed product would be 

 a little too strong even for the Galway Professors. 



Granular Limestones, Dolomites, etc. — So much space has been 

 devoted to the previous subjects that but little can be said under 

 the above headings. These chapters are by no means the least 

 interesting in the work, and the intimate acquaintance with the 

 Magnesian Limestone of Durham possessed by one of the authors 

 lends additional value both to the matter in the text and the 

 appendix. If the reader cannot at present accept the new interpre- 

 tation in all cases as the one which seems the most satisfactory, the 

 authors supply him with abundant material for reflection on topics, 

 which by their very nature are so obscure and difficult as to invite 

 the widest possible divergence of opinion. W. H. H. 



I^:EI=OI^TS j^^zlstid i^iaoozEZEZDHsro-s. 



Geological Societt of LoNDOasr. 

 March 8, 1882.— J. W. Hulke, Esq., F.R.S., President, in the 

 Chair. — The following communications were read : — 



1. "Additional Note on certain Inclusions in Grranite." By J. 

 Arthur Phillips, Esq., F.E.S., F.G.S. 



The author referred to certain rounded inclusions in granite which 

 were rich in mica. These he had described in his paper published 

 in vol. xxxvi. of the " Quarterly Journal," and had considered to be 

 contemporaneous segregations from the molten rock. He had, up 

 to that time, not found a case where one of the larger crystals of 

 felspar in a porphyritic granite occurred partly in the one, partly in 

 the other. Of late he had seen several, one of which he described 

 minutely, thus proving the correctness of his supposition. 



2. '-The Geology of Madeira." By J. S. Gardner, Esq., F.G.S. 

 Madeira consists almost wholly of sheets of basaltic lava of 



variable thickness interstratified with tuff scoria and red bole, cut 

 by innumerable dykes. In the central part of the island is a horse- 

 shoe-shaped valley, more than 4 miles in diameter, its bed 2500 feet 

 above the sea, its precipitous walls full 3000 feet high, rising here 

 and there to yet greater elevations, and forming a central point in 

 the mountain system of the island. This the author regards as the 

 basal wreck of a volcanic mountain, blown into the air bj^ an explo- 

 sion of exceptional violence. Fragments of the slopes of scorise 

 which once composed the inner shell remain on the peaks surround- 

 ing this amphitheatre. The dykes here are trachyte. The author 



