CHAP. XV.] 
THE SANDWICH ISLANDS. 
209 
extensive, the entire archipelago is volcanic, and the largest island 
is rendered sterile and comparatively uninhabitable by its three 
active volcanoes and their widespread deposits of lava. 
The ocean depths by which these islands are separated from 
the nearest continents are enormous. North, east, and south, 
soundings have been obtained a little over or under three thousand 
fathoms, and these profound deeps extend over a large part of 
MAP OF THE SANDWICH ISLANDS. ' 
The light tint shows where the sea is less than 1,000 fathoms deep. 
The figures show the depth in fathoms. 
the North Pacific. We may be quite sure, therefore, that the 
Sandwich Islands have, during their whole existence, been as 
completely severed from the great continents as they are now ; 
but on the west and south there is a possibility of more exten- 
sive islands having existed, serving as stepping-stones to the 
island groups of the Mid-Pacific. This is indicated by a few 
widely-scattered coral islets, around which extend considerable 
