168 
ANDERSON : THE VOLCANOES OF ICELAND. 
The lava near the craters is almost all of the corded or " pako- 
heoe " type, while lower down the valley immense fields of scoriaceous 
lava, or " aa" of the most bristling character are seen. The most 
probable explanation being that the lava, at the commencement of 
the eruption, contained much imprisoned steam and vapours which 
escaped in fiery froth, and solidified into the rough " aa," and was 
carried down the valley on the surface of molten lava, which, in 
places, is as much as 600 feet thick. The eruption was a prolonged 
one, and consequently the later lava had a prolonged simmering in 
the chimney or fissure during which it parted with most of its vapour, 
and when finally it flowed out it had little left, not sufficient to form 
a layer of froth, but only a few " giant's children " or blow-holes, of 
which some very fine examples occur near the craters. This sequence 
of events does not appear always to obtain. Near Hekla we saw a 
stream of lava, scoriaceous on the steep slope near its point of erup- 
tion, but corded with most beautiful regularity in parts where it had 
flowed tranquilly on the plain after parting with most of its vapour, 
and escaping from under the crust higher up. 
"We returned from the Skapta by way of the Fjallabaksvegr, a 
desert route of about ninety miles from the last house on the one 
side to the first on the other, and thence by Hekla, the Geysir, and 
Thingvalla ; but these have often been described, and space is wanting. 
It is currently believed in Iceland, and was stated in some of the 
public prints at the time, that a volcanic eruption or earthquake had 
taken place at Cape Reykjanses in October, 1887, by which a large 
new gid or chasm had been formed, separating a large rocky promon- 
tory, almost deserving the name of a mountain, from the main cape 
on which the lighthouse stands. This chasm, at least fifty feet wide, 
was pointed out to the author from a passing steamer, the captain 
declaring that he remembered the rocks before they were rent asunder. 
Here, then, appeared to be a case of the formation of one of the gias 
or chasms which form such a characteristic feature of Icelandic 
geology. There are several such on the Reykjamses peninsula, huge 
chasms several feet wide and of unknown depth, stretching for miles 
across the lava desert of which the district is composed. In this 
district they usually, though not always, have a throw of a few feet 
