6 Scientific Proceedings, Royal Dublin Society. 
annual proceeding, which we hope will lend additional attraction 
to our Society. We must turn again to business and point out 
that the annual field excursion, so pleasant, not only geologically, 
but otherwise, also, is to be only for our own Fellows, and that 
our allies of the Royal Dublin Society, in order to partake of the 
advantages thereof, must become naturalized as Fellows of our 
Society. The precise arrangements have not yet been decided 
upon ; but when they are they will be made known. 
It is the usual, but not invariable, practice to give in the 
Anniversary Address a réswmé of our proceedings during the 
past year. I propose to omit this on the present occasion, 
there being precedent for so doing, and to invite the attention of 
the Society to a matter which is to geologists of the utmost 
importance, viz., the physical argument for the restriction of 
geological tume. Though this is a question which lies somewhat 
cut of the usual line of geological discussion, we cannot 
afford to pass it by. When cosmogonical or semi-cosmogonical 
arguments are brought against what seem to be in themselves 
unavoidable geological conclusions we are compelled to go into 
those arguments for ourselves. As the question we have to 
consider is by no means a new one, we may enter upon it at once 
without any further preface. 
Professors Sir William Thomson and Guthrie Tait object, as 
physicists, to the geologists, that, for several reasons, the whole 
reach of geological time must be very much less than that which is 
generally supposed to be necessary for the explanation of various 
geological phenomena. We need not now go into the reasons for 
believing that the geological changes, operations, and evolutions, 
of which we see evidence, must have required an enormous space 
of time for their accomplishment. The argument from denudation, 
for instance, has been very strongly presented, quite lately, by Dr. 
Croll in the Quarterly Journal of Science, July, 1877. Let us, 
however, acknowledge that some geologists have been too free in 
the assumption that they had practically unlimited time at their 
disposal; they were looking at things too exclusively from their 
own point of view, and needed to have it pointed out to them 
that there were other momenta of the question which they were 
altogether neglecting. Let us cheerfully acknowledge our ob- 
ligations to the physicists for haying impressed this upon us; 
