On Cornish Earthquakes. 571 



2. ' On some Ironstone Fossil Nodules of the Lias.' By E. A. 

 Walford, Esq., F.G.S. 



3. ' Additional Notes on the Glacial Phenomena of Spitsbergen.' 

 By E. J. Garwood, Esq., M.A., F.G.S. 



This paper contains the results of additional observations on the 

 ice of Spitsbergen made by the writer in 1807. The inland ice 

 visited occupies two distinct areas, separated by Dickson's Bay and 

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

 centres of each area, with supplementary radiating-point s on the 

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

 may be regarded as nunatakkr. 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 stoso-seitc of a 

 nunatak moraine-material is often discharged. The movement of the 

 ice has frequently con verted 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 light 

 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. 



November Sth. — W. Whitaker, B.A., F.B.S., President, in the Chair. 



The following communications were read : — 



1. 'On the Cornish Earthquakes of March 20th to April 2nd, 

 1808.' By Dr. Charles Davison, M.A., F.G.S. 



The importance of these three slight earthquakes lies chiefly in the 

 unusually clear evidence that they furnish with regard to the origin 

 of the double series of vibrations in one of the shocks, and to the 

 continuous displacement of the seismic focus along the surface of 

 the originating fault. The second earthquake — that of April 1st — 

 was the strongest of the series, and the account of it is based on 

 80 records from 56 different places. Two distinct shocks were 

 recorded at 25 places, the second being the stronger. The focus of 

 the first earthquake was about a mile in length ; that of the second 

 was probably not less than 5 miles, and its centre being about a 

 mile E. 33° N. of the former, it probably included the focus of the 

 first earthquake. The focus of the third shock was probably included 

 in that of the second. The strike of the rocks near Mullion, a 

 thrust-plane hading to the south-east, the strike of the lodes near the 



