194 
LETTERS FROM HIGH LATITUDES. 
ance of these rocks arises from the fact of their being 
built up in layers of trap, alternating with Neptunian 
beds; the disintegrating action of snow and frost on 
the more exposed strata having gradually carved their 
sides into flights of terraces. 
It is in these Neptunian beds that the famous 
surturbrand is found, a species of bituminous timber, 
black and shining like pitch coal, but whether belonging 
to the common carboniferous system, or formed from 
ancient drift-wood, is still a point of dispute among the 
learned. In this neighbourhood considerable quantities 
both of zerlite and chabasite are also found, but 
generally speaking, Iceland is less rich in minerals 
than one would suppose; opal, calcedony, amethyst, 
malachite, obsidian, agate, and feldspar, being the 
principal. Of sulphur the supply is inexhaustible. 
After steaming down for several hours between 
these terraced hills, we at last reached the extremity of 
the fiord, where we found the “Saxon” looking like 
a black sea-dragon coiled up at the bottom of his den. 
Up fluttered a signal to the mast-head of the corvette, 
and blowing off her steam, she wore round upon her 
heel, to watch the effects of her summons. As if roused 
