THE SUB-OVEANIC DEPRESSION, ETC. 431 
or three-quarters of an hour, I have seenit as it approached the 
land, rapidly increase in size to about a square mile. One could 
hardly imagine that all that water could be deposited in such a 
small space. Of course if you get mountain ranges of 20,000 feet 
with a warm south-west wind blowing, you can imagine the 
enormous quantity of water that would be precipitated. Then 
as to the movement of sand, one can hardly imagine, unless one 
has seen it, the action of the wind on sand and the height of the 
sand wave. Jt is very much like the formation of a wave of the 
sea, and one sees how quickly the sand wave will move directly 
there is any wind of any strength. One sandhill I remember 
distinctly, about three-quarters of a mile long, and the edge of it 
was just as sharp as the back of a knife. Directly any wind blew 
the edge of sand fell down by its own gravity, a fresh edge being 
formed and its face always standing at a certain angle. So with 
a bay lke that of Biscay you can understand any quantity of sand 
being thrown up. 
I am sure we desire to convey our best thanks to Professor 
Logan Lobley for his very interesting paper, which I think has 
completed the whole question that was brought before us by 
Professor Hull on a previous occasion. 
The meeting then adjourned. 
