A. FE. Verrili—The Bermuda Islands. 467 
from it. Some of these are connected with the sea, like Tuckers 
Town Bay, Trott’s Pond, and Peniston’s Pond; others are separated 
from it by narrow and low divides or ridges. In severe storms the 
sea pours in large quantities over the low divide into Peniston’s 
Pond, which is the largest of the ponds, so that ultimately, and at 
no distant time, it will doubtless form a breach and thus convert the 
pond into a bay or harbor, like Hungry Bay and many others. 
Hungry Bay was evidently at one time a pond of the same kind, 
which has been breached by the sea. The tide now flows in and out, 
through a narrow channel, in a rapid current. This bay is shallow 
and the inner end terminates in a dense mangrove swamp of con- 
siderable extent. It is a favorable place for zoélogical collecting. 
When the interior valleys or sinks are not quite so low, but yet 
extend below the level of the sea, they usually form swamps, peat 
bogs, or marshes, with thick beds of peat or muck. Pembroke 
marsh and Devonshire swamp are large peat bogs of this description. 
Borings have shown that the peat in Pembroke marsh is about 
40 feet deep, and its bottom extends many feet below the level of 
the sea, showing that the land has subsided considerably since the 
beginning of its formation, for peat does not form in the salt ponds 
or bogs. Peat bogs have also been dredged up during the harbor 
improvements, at considerable depths. (See Geology.) 
The vegetation in some of the swamps is very dense and luxuriant. 
This is the case especially in Pembroke swamp. The Palmetto 
grows tall and slender in such places (fig. 32). Among other plants, 
the ferns are very conspicuous. Some of these grow to large size, 
especially the two species of Osmunda, which are also found in the 
northern United States; the common brake or bracken (Peris aqui- 
lina); and the Marsh Fern (Acrostichum aureum), a large West 
Indian species. (See Part III, ch. 24, Botany.) 
Absence of Streams and Springs. 
Owing to the great porosity of all the limestone rocks, surface 
water does not collect sufficiently at any place to form streams,. 
springs, nor ponds. Rain-water, collected in cisterns, is the uni- 
versal water supply,* and owing to the abundant rains, it seldom 
fails, with ordinary care. The roofs of the houses are mostly 
covered with slabs of limestone, cemented, and arranged to catch all 
* There are a few exceptions to this rule, for three or four recent wells, of 
moderate depth on high land, have proved successful. 
