A. EF. Verrill—The Bermuda Islands; Geology. 61 
by winds, drift-wood, birds, etc., thus forming a new fauna and flora, 
combined with some remnants of those that had survival the glacial 
storms. 
9. Reélevation of Bermuda. 
There is considerable evidence that these islands underwent a 
slight reélevation of about six to ten feet, after the period of greatest 
depression. If this be true, its period corresponded, in all prob- 
ability, to that in which Nova Scotia, Eastern Canada, and New 
England underwent a much greater reGlevation in post-glacial or 
Quaternary time. 
Such a reélevation, of small amount, would best account for the 
various local deposits of beach-rock, containing recent marine shells 
and corals, now found elevated from 6 to 15 feet above the sea, 
This will be discussed later. 
10. Consolidation of the Sands ; formation of the Aolian lime- 
stones and “base rock.” 
During the whole period of the accumulation of the shell-sands, 
a process of consolidation or cementation of the sands into softer or 
harder limestone has been going on beneath the surface of the land,* 
but not uniformly. This is brought about by the rain water, which 
always contains carbonic acid in solution, which dissolves a certain 
amount of the limestone as it percolates through the sands, forming 
calcium bicarbonate in solution. This solution, when exposed to the 
air, and especially when it evaporates, deposits calcium carbonate or 
crystalline calcite, either between the particles of sand, binding them 
together, or in the form of stalactites and stalagmites, when it drips 
into caverns, as is well known. 
But in the rainy and warm climate of Bermuda, this process goes 
on with unusual rapidity. In fact, the sands and porous limestones, 
below a certain distance from the surface, seem to be saturated with 
the lime solution, for many of these limestones, which are so soft 
that they are quarried by large chisels and cut into regular building 
stones with ordinary saws, as easily as wood, become quite hard and 
suitable for building+ after exposure to the air for a few weeks. 
* There is no evidence at Bermuda that the shell-sand and marl ever consoli- 
date into limestone when wholly submerged beneath the sea. These materials 
are everywhere loose to a great depth, in the sounds. 
. + See these Trans., xi, p. 431, fig. 11; ‘‘ The Bermuda Islands,” p. 19, fig. 11. 
Trans. Conn. AcapD., Vou. XII. 5 June, 1905. 
