162 
EEPOKTS OF MEETINGS. 
tioii and deposition are thus the two great processes at work in 
altering the earth’s surface. The Uniformitarians were succeeded 
by the Evolutionists, who ascribe the changes to physical causes, 
the sun being, as it were, the mainspring, which sets the 
machinery in motion, causing rain, wind, and other meteorological 
phenomena, all which are factors in the forces at w'ork. The 
heat lost by the earth may in great part account for the eleva- 
tions and depressions on its surface, owdng to the difference in 
the rate of contraction between the interior and exterior. Sir 
W. Thomson has calculated that it is between 100 and 200 
millions of years since the earth began to consolidate; the 
geologists assign from 50 to 500 millions of years as the period. 
As we go back to the past, we must naturally expect that the 
forces at work were more powerful, owing to the increased 
temperature ; and as a proof of this, we find that in layers of 
equal thickness in the Palaeozoic and Tertiary rocks, we have the 
proportion of extinct species, as one in the former, to four in the 
latter, owing to difference in the rate of deposition ; and the 
conclusion arrived at is, that the decreasing energy of the sun 
and earth, must have led to diminishing rapidity in the action of 
the main factors in geologic change, viz., denudation, repro- 
duction, and elevation and depression of strata. 
At the following meeting on the evening of March 4th, Mr. 
W. J. Fuller’s paper on “The Breathing Apparatus of certain 
Aquatic Larvae ” was read by the Hon. Secretary in the author’s 
absence. This communication appears in this year’s Proceedings. 
Dr. Burder also gave the result of “ Recent Investigations on 
the Course of Storms,” which, illustrated by some excellent 
charts executed under the auspices of the United States Govern- 
ment, will be found in the preceding pages. 
At the meeting on the 8th of April, Mr. Leipner read the- 
following paragraphs from the Natal Colonist of March 2nd,. 
1880 ■ 
