ysiology, so are these phaenomena the
subject-matter of an analogous telluric physiology, to which we
sometimes give the name of meteorology, sometimes that of physical
geography, sometimes that of geology. Again, the earth has a place in
space and in time, and relations to other bodies in both these
respects, which constitute its distribution. This subject is usually
left to the astronomer; but a knowledge of its broad outlines seems to
me to be an essential constituent of the stock of geological ideas.

All that can be ascertained concerning the structure, succession of
conditions, actions, and position in space of the earth, is the matter
of fact of its natural history. But, as in biology, there remains the
matter of reasoning from these facts to their causes, which is just as
much science as the other, and indeed more; and this constitutes
geological aetiology.

Having regard to this general scheme of geological knowledge and
thought, it is obvious that geological speculation may be, so to speak,
anatomical and developmental speculation, so far as it relates to points
of stratigraphical arrangement which are out of reach of direct
observation; or, it may be physiological speculation, so far as it
relates to undetermined problems relative to the activities of the
earth; or, it may be distributional speculation, if it deals with
modifications of the earth's place in space; or, finally, it will be
aetiological speculation, if it attempts to deduce the history of the
world, as a whole, from the known properties of the matter of the earth,
in the conditions in which the earth has been placed.

For the purposes of the present discourse I may take this last to be
what is meant by "geological speculation."

Now uniformitarianism, as we have seen, tends to ignore geological
speculation in this sense altogether.

The one point the catastrophists and the uniformitarians agreed upon,
when this Society was founded, was to ignore it. And you will find, if
you look back into our records, that our revered fathers in geology
plumed themselves a good deal upon the practical sense and wisdom of
this proceeding. As a temporary measure, I do not presume to challenge
its wisdom; but in all organized bodies temporary changes are apt to
produce permanent effects; and as time has slipped by, altering all the
conditions which may have made such mortification of the scientific
flesh desirable, I think the effect of the stream of cold wat