546 Geological Society . 



Wyre Forest, South Staffordshire, Warwickshire, Leicestershire, and 

 North Staffordshire are all essentially similar ; and observers are 

 urged to look out for coal-seams, plant-remains, and Sjpirorbis- 

 limestones. 



November 6th. — Dr. Henry Woodward, F.R.S., President, 

 in the Chair. 



The following communications were read : — 



1. * The Serpentine, Gneissoid, and Hornblendic Eocks of the 

 Lizard District.' By T. G. Bonney, D.Sc, LL.D., F.E.S., F.G.S., 

 Professor of Geology and Mineralogy in University College, London. 



After some introductory remarks the author states that in 

 company with the Rev. E. Hill, and in consequence of their work, 

 in Sark, he again investigated the question of the genesis of the 

 hornblende-schists at the Lizard, and was able to overcome the 

 difficulties which formerly withheld him from attributing an igneous 

 origin to the schists themselves and their banded structures to 

 fluxional movements during consolidation. Here also, as in Sark, 

 there is some evidence of this banding being the result, at any rate 

 in places, of a mixture of a less and a more basic material. Addi- 

 tional evidence is given as to the genesis of the granulitic group 

 and its relations to the hornblende-schist. Moreover, in consequence 

 of the paper by Messrs. Pox and Teall, published in the Society's 

 Journal (vol. xlix. p. 199), the author has again examined (with 

 Mr. Hill) every section which he could discover to bear on the 

 relations of the serpentine, the hornblende-schist, and the granulitic 

 rock. A number of instances are quoted, where the serpentine splits 

 open or rumples the bands of the granulitic rock, or cuts across them. 

 He shows that in the sections at Potstone Point and elsewhere the 

 serpentine is welded to the hornblende-schist, cuts across its banding, 

 and behaves generally as an intrusive rock, while the rare cases of 

 apparent interstratification of the two prove to be the results of 

 the inclusion and occasional very local melting down of the latter 

 by the former rock. He maintains that the relations of the serpen- 

 tine to the granulitic and the hornblendic groups are inexplicable 

 on the hypothesis of an igneous complex, so far as he understands 

 the meaning of that term, or of a folding in a solid condition or 

 any other form of dynamometamorphism, and he maintains his 

 original opinion that the serpentine (i. e. the original peridotite) is 

 intrusive in the other rocks. 



The paper also deals with some minor points in the geology of 

 the Lizard ; the author supplying some additional particulars about 

 the serpentine at Porthkerris and Porthallow, and explaining that 

 he has found the rocks on the south side of Porthoustock Cove to 

 be only a continuation of those which form the crags south of the 

 opening of the Cove, though they are generally less well preserved : 

 namely, a fine-grained gabbro, intrusive in the ordinary Crousa 

 Down gabbro, and ' greenstone ' dykes cutting both of these, 



