26 Reports and Proceedings. 



to time by fissures and the agency of rain and frosts, the position as 

 well as magnitude of these openings being changed, whether by the 

 falling in of their sides, the gradual deposit of new material from 

 water running over the surface, or by their being enlarged to form 

 regular valleys. So rapid do these changes take place, that vegeta- 

 tion cannot well exist ; there are no trees — hardly even bushes — 

 there is not time for them to grow. In some districts (Algeria, 

 Ionian Isles, &c.) " an air of wild desolation characterises the land- 

 scape," — vast naked expanses of loose soil may be travelled over. 

 Vegetation is in a certain sense conservative, as when the ground is 

 overgrown, the denuding effect of the weather is reduced. In his 

 observations on the Channel Islands, Prof. Ansted mentions that the 

 breaking up of the rocks which form the vast and constantly shift- 

 ing heaps of sienite is due to rain and frost, assisted by vegetation, 

 — the removal alone is effected by the sea, and that imperfectly. 



In some parts of these Islands the Greenstone Eocks are de- 

 composed, and form a sand and gravel, with apparent boulders of 

 the rock itself. 



Prof. Ansted gives numerous other notes on the disintegration of 

 rocks, and concludes with a few remarks on the importance of 

 Physical Geography as a key wherewith to unlock some of the 

 mysteries of Geology. 



Geologists are at the present time so much at variance as to the 

 amount of credit due to Subaerial denudation on the one hand, and 

 to Submarine on the other, that careful observations on the denuda- 

 tions going on at the present time are of the utmost value. So vast 

 is the amount of sediment brought down by rivers, and to stich 

 great distances is it carried away by currents and deposited over the 

 bed of the ocean (as Lyell shows in the last edition of his " Prin- 

 ciples," vol. i.), that perhaps, when looking at the immense thickness 

 of sedimentary deposits containing marine shells, we are apt to 

 attribute too much to the sea, when a very considerable part of the 

 sediment might have been brought down by rivers, the result of 

 Subaerial Denudation. 



Geological Society of London. — Nov. 25th, 1868. — 1. " On 

 Floods in the Island of Bequia." By G. M. Browne, Esq. Com- 

 municated by the Secretary of State for Foreign Affairs. 



On the 17th of March, at 8 o'clock p.m., a steady strong wave was 

 seen bearing down upon Admiralty Bay ; it had no perceptible crest, 

 and was three feet in height ; it encroached upon the land to distances 

 varying from 70 to 350 feet. A second smaller wave followed. No 

 shock of an earthquake was felt. 



Discussion. — Dr. Duncan wished for some explanation of these 

 earthquake waves, more especially with regard to the effects of sup- 

 posed cataclysmic waves. He considered that they arose from sud- 

 den changes in the level of shoals or littoral tracts, and not from 

 deep-sea disturbances. 



