264 Dr. Mac Culloch on the 
of islands from the sea by the action of volcanoes, an occurrence 
which has often happened; and by the more common circum- 
stances that attend these in ordinary cases, as in Italy, America, 
and elsewhere. 
But this volcanic action has been supposed to be trifling and 
partial, and incapable of being resorted to for the solution of any 
other cases than those where the process has actually been 
witnessed, or can be clearly demonstrated. ‘The object of this 
paper is to shew that it has produced far greater effects 
than has commonly been imagined, and that some of the most 
singular and interesting geological phenomena that are known, 
can be most satisfactorily explained in this manner. 
Before describing the two cases which I have selected for 
examination, I must, however, notice the simpler one of ordinary 
volcanic islands, as illustrating the more complicated appear- 
ances under review. One of the most noted of these lies near 
Santorini, in the Greek Archipelago. The formation of this, in 
consequence of a submarine eruption, commenced in 1707, and 
in less than a year it had attained a circumference of five miles, 
with an altitude of forty feet. A similar one, of smaller dimen- 
sions, was also formed in the same place not long after; and, 
according to Pliny, Therasia, Automali, and Thia were also 
thrown up in this neighbourhood in the same way, in ancient 
times. In like manner, islands have been generated near Ice- 
land, and the Azores, at recent periods; and but a few years 
are past since a small island, to which the name of Sabrina 
was given, was thrown up in the neighbourhood of these latter. 
These events seem to have frequently occurred in the Pacific 
Ocean; and, though some of these volcanic islands are low, 
they occasionally obtain a considerable elevation. Ascension 
seems to be a very satisfactory instance of this nature, though 
its actual formation has not been witnessed, as in the cases just 
mentioned ; and St. Helena appears to furnish another example 
of the same nature. 
In some instances these islands seem to be entirely formed of 
stones and scoria, and probably also of lava, thrown out from 
the volcanic aperture beneath the sea. These, gradually 
