Oorrespondenee — Professor T. G. Bonney. 431 



Wijde Bay. The radiating-point lies somewhat north-west of the 

 centres of each area, with supplementary radiating-points on the 

 north and east. The group of peaks including the Three Crowns 

 may be regarded as uunatakkr. The valley-bound ground-ice does 

 not necessarily travel in the same direction as that of the surface. 

 The effect of nunatakkr on the surface of the ice-sheet was studied, 

 and from this it was often found possible to infer the existence and 

 position of buried mountain-ridges. On the stoss-seite of a nunatak 

 moraine-material is often discharged. The movement of the ice has 

 frequently converted the ice-bridges across crevasses into arches and 

 tunnels, some of which carry part of the drainage of the ice-sheet. 



Portions of old stranded ground-moraines, formed when the ice 

 was more extensive, were sometimes found to have fallen upon the 

 lowered ice-sheet and to be mingled with modern moraine-material. 

 Englacial and superficial rivers are described, and one of the latter 

 was found to be depositing gravelly material along a line at right 

 angles to the valley down which the ice was flowing. 



Certain observations on the rate of movement of the ice-sheet 

 seem to indicate that this is not less than 15 to 20 feet in 24 hours ; 

 while the glaciers near the sea-margin appear to be travelling about 

 25 feet in the same time. 



The action of sea-ice is described, and it is inferred that a certain 

 amount of rounding and scratching of shore-rocks, and possibly part 

 of the smoothing of boulders, may be due to this agent. 



4. "Additional Notes on the Vertebrate Fauna of the Rock-Fissure 

 at Ightham (Kent)." By E. T. Newton, Esq., F.R.S., F.G.S. 



Since the previous paper on the Ightham -fissure fauna published 

 •by this Society about five years ago, numerous additional specimens 

 have been obtained, not only by Mr. Lewis Abbott, but also by 

 Mr. Frank Corner and Mr. Kennard. 



The present paper gives a very brief account of the new forms 

 which have been discovered and identified during the last five years, 

 with remarks upon some important additional remains of Mustela 

 robusta, and of the SpermopMlus which is now referred to the species 

 erythrogenoides of Falconer. This paper adds some 19 new forms to 

 the fauna of the Ightham fissure. 



'•%.../■•'■' The next Meeting of the Society will be held on Wednesday, 

 :NTovember 8th, 1899. 



O O S, la E S :F O IsT ID DE InT G IE. 



EOCK-WEATHERING, SEEPENTINIZATION, ETC. 



Sir, — Both Mr. Merrill and Mr. Holland deserve the thanks of 

 geologists for their suggestive papers on certain forms of rock 

 change, and the distinction drawn by the former (p. 354, Geol. Mag., 

 August, 1899) between ordinary 'weathering' and more deep-seated 

 changes in rocks is of great importance. The subject is one which 

 my own work has often brought before me, though, as other 



