Geological Society of London. 93 



not to depend solely on chemical causes, but to be influenced by the 

 conditions under which the rocks have cooled down. 



Although these rocks are not highly altered ones, yet they afford 

 admirable opportunities of studying the incipient changes in their 

 constituent minerals. The nature of these changes is discussed, and 

 they are referred to the following causes : — (1) the corrosive action 

 of the surrounding magma on the crystals ; (2) the changes produced 

 by solvents acting under pressure in the deep-seated masses (these 

 have been already described under the name of " schillerization ") ; 



(3) the action of heated water and gas escaping at the surface ; 



(4) the action of atmospheric agents on the rocks when exposed by 

 denudation ; and (5) the changes induced by pressure during the 

 great movements to which rock-masses are subjected. 



II.— Jan. 13, 1886.— Prof. T. G. Bonney, D.Sc, LL.D., F.K.S. 



President, in the Chair. 



The President said, It may not be known to all present this 

 evening that during the past week we have lost a well-known 

 member of forty years' standing. Prof. John Morris died last 

 Thursday, and to-day some of us have stood by his grave 

 in Kensal Green Cemetery. The Society has lost its most 

 learned member, and many of us have been deprived of a very 

 dear friend. 



1. " On some Fish-remains from the Tertiary Strata of New 

 Zealand." By James W. Davis, Esq., F.G.S. 



A number of fossil fish-remains from Tertiary beds in New Zea- 

 land have been forwarded to the author by Captain F. W. Hutton, 

 and were described in the present paper. The forms of which 

 descriptions were given are two new species of Lamna, Carcharodon 

 anynstidens, Agassiz, and a new Carcharodon, one new species of 

 Notidanus, one of Myliobatis, and one referred to Sparnodus. All 

 the above are founded on teeth. A vertebra of Lamna and a fish- 

 spine were also described, and the collection contained a specimen 

 regarded by the author as a fragment of a Eeptilian tooth. 



2. " On a recent Section through Walton Common, exposing the 

 London Clay, Bagshot Beds, and Plateau-gravel." By W. H. 

 Hudleston, Esq., F.R.S., F.G.S. 



During the past autumn the widening of the line between Walton 

 and Weybridge stations has afforded a very interesting section in the 

 above beds, showing their relations to each other with considerable 

 clearness. Walton Station is 68 feet above O.D., and immediately 

 to the westward the section described in the paper commences, the 

 surface of the country gradually rising to a height of about 120 feet 

 in the plateau which separates the drainage of the Mole from the 

 drainage of the Wey. This plateau is connected on the south by a 



