STRUCTURE OF THE TITTERSTONE CLEE HILL. 
223 
sequently removed by denudation. There is every reason to 
believe that the two Clee hills have been at one time 
continuous, and that the valley between them has been 
caused by denudation. 
It is not easy to form a very clear idea of the vast 
natural operations of which I speak, and to some I fear my 
words may seem to partake of romance and imagination. 
Yet, you must remember what may possibly be going on at 
this very moment, unknown to us, in some quarter of our 
own globe. Sitting, as you are now, among these rocks, 
amid this peaceful scene, it is not easy to realise the fact 
that there are spots on the surface of the earth which are 
the scene of the most violent convulsion; that there are at 
this moment, in Hawaii, lakes of molten lava some twelve 
miles long, in a state of fusion, and that, without any 
perceptible disturbance whatever to this quarter of the earth, 
only a year or two ago a mountain in Java, some 2,000ft. 
high, was projected twelve miles into the sea. Again, so 
lately as the year 1783, a stream of lava issued from Skaptur 
Jokul, a mountain in Iceland, which, separating into two 
portions, extended altogether to a distance of ninety-eight 
miles, filling valleys varying in breadth from a narrow gorge 
to fifteen miles, and in depth from 100ft. to 600ft. Cast your 
eyes over the valley which lies beneath us, and fancy a 
stream of molten matter not only filling it but extending 
two-tliirds as far as London is from here, and thus you may 
obtain a practical idea of the vast operations which are going 
on even in the present day. 
The question is often asked, what underlies—what are the 
foundations of all the rocks which compose the earth’s crust ? 
and it was long supposed that they must be of igneous origin. 
Later discoveries have, however, tended to modify this 
opinion. That our globe has been the gradual condensation 
of nebulous matter in a state of intense heat, and that 
immense volumes of molten matter exist within the bowels 
of the earth there is every reason to believe. Yet we are 
unable to say of any mass of granite or basalt that in it we 
behold the primordial floor on which all subsequent forma¬ 
tions have been laid down ; since sedimentary strata of every 
age are found penetrated by these volcanic rocks, which have, 
therefore, been obviously formed subsequently to the depo¬ 
sition of the others. All we can say is that so far as we can 
judge there are evidences of a series of operations extending 
to a distance in past time which is practically infinite, and in 
which the deposition of rocks from water, their denudation 
by atmospheric agencies, and outbursts of volcanic matter, 
have gone on concurrently from time to time. 
