306 * THE ATLANTIC. [OHAP. IV. 
able, and we constantly plucked and smelled it without its pro- 
ducing any unpleasant effect. The tide was with us when we 
regained the Flats Bridge, and the galley shot down the rapid 
like an arrow, the beds of scarlet sponges and the great lazy 
trepangs showing perfectly clearly on the bottom at a fathom 
depth. 
Every here and there throughout the islands there are groups 
of bodies of very peculiar form projecting from the surface of 
the limestone, where it has been weathered. These have usu- 
ally been regarded as fossil palmetto stumps, the roots of trees 
which have been overwhelmed with sand, and whose organic 
— 
Fie. 79.—Calcareous Concretion simulating a Fossil Palm-stem, Boaz Island, Bermudas. 
matter has been entirely removed and replaced by carbonate of 
lime. Fig. 79 represents one of the most characteristic of these 
from a group on the side of the road in Boaz Island. It is a 
cylinder, a foot in diameter and six inches or so high; the up- 
per surface forms a shallow depression an inch deep surrounded 
by a raised border; the bottom of the cup is even, and pitted 
over with small depressions like the marks of rain-drops on 
sand; the walls of the cylinder are rough, with transverse ridges 
and grooves singularly like the lines of insertion of endogenous 
leaves. The cylinder seems to end a few inches below the sur- 
face of the limestone in a rounded boss, and all over this there 
