130 
VOLCANIC CRATERS AND EXPLOSIONS—DISCUSSION. 
gave, at a meeting of this Society, at which I had not the good fortune to be 
present, an account of several terrible volcanic outbreaks which had occurred in 
the West Indies, and three years ago he gave an equally instructive paper on 
the volcanic phenomena of Guatemala. Probably no one in this country has 
seen more volcanoes or more eruptions, fortunately so far without injury to 
himself, than our lecturer this evening, and to-night he will take us to several 
typical volcanoes in various parts of the world, and by means of his own de¬ 
scriptions and a fine series of slides, will illustrate the different kinds of explosions 
and the various character of craters. I will now ask Dr. Tempest Anderson to 
deliver his lecture. 
Dr. Strahan (after the paper): I think you will agree that it has been a great 
privilege to see this wonderful series of photographs of Dr. Tempest Anderson’s, 
gathered from all parts of the world in which volcanoes are active. The British 
Isles have been said to contain a sample of everything connected with geology— 
to be in themselves a perfect little museum, but there is one thing which they do 
not possess, and that is an active volcano, though I do not mean to say that that 
is a matter for regret. But if we have no active volcanoes we have many dead 
ones. The British Isles are situated on the margin of the European-Continental 
area, in a position where land and sea meet, and in which volcanoes are frequently 
developed. We may, therefore, suppose that our freedom from active volcanoes 
at the present moment is temporary. Of course in past times there has been 
plenty of igneous action in the British Isles; for example, some of the Western 
Isles of Scotland are the remains of a prodigious mass of basalt which was poured 
out, as supposed, from a fissure, for no volcanic cone appears to have been reared, 
but a long crack opened in the crust of the earth, from which lava welled out in huge 
quantities. The islands I refer to are merely remnants of that huge mass which have 
been left by the sea. But what I have in my mind at the moment is a beautiful 
study of the results of a volcanic outburst which may be seen in the cliffs near 
Weston-super-Mare. There, in the Carboniferous limestone teeming with fossils, 
you may see proof that the bed of the sea was suddenly overspread by lava. The 
molten rock, cooling more or less quickly under the sea, developed that peculiar 
structure which has been alluded to by Dr. Tempest Anderson as pillow-struc¬ 
ture. Here, therefore, is a case in which his studies of lava flowing into the sea 
have proved of much value to geologists, for they enabled us to see under what 
conditions it could happen that the lava should be divided up into huge pillow¬ 
like masses with limestone in between. While this eruption was going on all the 
organisms were driven away. But presently the lava ceased to flow, and then 
some of the organisms began to struggle back, but only a few of the more hardy 
spscies, for the rock which lies next above this lava consists chiefly of volcanic ash. 
There were for a time alternations of coarse and fine ash, but gradually the showers 
abated and the water cleared. The episode came to an end, the teeming fauna of 
the Carboniferous-limestone period overspread the spot, and perfect tranquillity 
reigned. All this is recorded in the cliff, and anybody can see it by hammering 
over the rocks. But after all the rocks are so to speak dead, and it is as well 
that we should know what the scene was like when the volcano was alive. 
Apart from witnessing an actual eruption, there is no better way of realizing 
the scene than having the great privilege of seeing a series of photographs pre¬ 
sented by Dr. Tempest Anderson. The series has been got in the course of 
many years at considerable expense and trouble, and I expect (though he has 
not enlarged upon that subject) with no little personal risk. 
Mr. Bruce Mitford : I have little to add to the interesting and instructive 
lecture which Dr. Tempest Anderson has given us, apart from a few observations 
