118 Anniversary Address to the 
comprised from south to north between the 16th and 55th 
degrees of latitude, and through much of its course exhibit- 
ing a breadth of 1800 miles. In the Himalaya, nummulitic 
rocks attain an elevation of more than 14,000 feet. 
It will ever be a matter of just pride to our Society, that 
within our meeting-room and in our proteedings the main task 
was effected of clearing up the mist that clouded so long the 
geological history of the great nummulitic formation, and 
that here it is our indefatigable colleague, Sir Roderick Mur- 
chison, effected this great advance in tertiary geology. And 
now that the paleontology of the Nummulites has been made 
as clear as noon-day by the genius and labour of M. d’Archiac, 
it will ever be a matter of congratulation to us that the cabi- 
nets of our Society and the collections of its Members were 
freely and heartily placed at his disposal, and have proved of 
some value towards enabling him to perfect his researches. 
The information now given, as far as I am aware, is 
new to geological language, and involves an idea which, al- 
though hypothetical, | wish to put forth upon this occasion. 
I am strongly impressed with the belief, that, fanciful though 
it may seem, there is within it the germ of a great geological 
truth. I have spoken of genera concentrating towards the 
paleozoic pole, and vice versa, of the substitution of groups, 
and the opposition of the more ancient to the mesozoic and 
modern faunas. ‘The phrases have been incidental, and arose 
naturally out of the subjects under commentary, but the idea 
that lies at the base of them, whether true or fallacious, re- 
quires to be stated, and there cannot be a better opportunity 
than the present for venturing to start this fresh geological 
hare. 
Every geologist whose studies have been equally or nearly 
equally directed to the organic phenomena of the three great 
sections of time usually received, Paleozoic, Mesozoic, and 
Tertiary or Cainozoic, cannot fail to have been struck with 
the greater value of the difference between the first or oldest 
section and the two newer divisions taken together, than be- 
tween the first and middle terms and between the latter and 
the last. The degree of organic difference between the upper 
mesozoic and the lower tertiary epochs is rather more, but 
