428 Proceedings of the Royal Society 
50 feet higliT The extent to which shelly sand was thrown up by 
the waves on the shores of the island, and then blown by the S.W. 
winds, so as actually to form hills of 180 feet in height, had been 
described by Lieut. Nelson, and the author himself distinctly 
remembers them, along the south side of the island. It seemed 
probable that the rain-water, containing as it does a certain amount 
of carbonic acid gas, had, by percolating through the sand-dunes 
in ancient times, hardened and consolidated the calcareous sand, 
down to a certain depth, into solid rock ; and this result would be 
all the more likely if, at a former period of the earth’s history, as 
many geologists supposed, the earth’s atmosphere then contained a 
larger proportion of carbonic acid gas. The compact limestone 
rock having been formed in this way, enclosing and lying above 
huge masses of sand, it was suggested that in the course of time 
the sand had been undermined and washed out by the action of 
the sea. It was understood that every one of the Bermuda caves 
are at or near the sea-level, and have pools of salt-water in them. 
3. Meteorological Observations on Storms of Wind in October, 
November, and December of 1863. By Alexander Buchan, 
M.A., Secretary to the Scottish Meteorological Society. 
The author had traced eleven distinct storms of wind passing 
over parts of Europe, between the 26th October and 18th December. 
With the view of ascertaining the state of the atmosphere during 
the progress of these storms, in respect of pressure, temperature, 
wind, cloud, and rain, he had collected observations from all parts 
of G-reat Britain and Ireland, as well as from many places on the 
Continent. He found that each storm was marked by concentric 
circles of equal atmospheric pressure. G-enerally, the point of 
greatest barometric depression was 28'5 inches, round which, as a 
centre, the isobarometric lines could be traced up to 30 inches. 
These isobarometric lines, especially when near the central area 
of minimum pressure, were often circular, or nearly so ; — when they 
were elliptic, the longer axis generally coincided with the direction 
in which the storm moved. 
In the great majority of the cases investigated, the storm moved 
