Reports & Proceedings—Geological Society of London. 135 
effect of buoyancy owing to this difference of density: this group of 
hypotheses, therefore, may be regarded as one of support by flotation. 
They involve a migration of matter from outside to beneath the 
range, they allow of a considerable local departure from exact 
balance between load and support (or topography and compensation), 
so long as the defect in one tract is balanced by an excess in an 
adjoining one, and they provide for an adjustment of any disturbance 
of this balance. 
The geodetic observations in the Himalayas show that there is 
a defect of compensation in the outer hills, which increases in amount 
until at about 50 miles from the edge of the hills it reaches an 
equivalent to an overload of about 2,000 feet of rock. In the 
interior of the Himalayas the only observation yet published shows 
that at about 140 miles from the edge of the hills this overload has 
disappeared, and compensation is in excess. The variation in the 
balance between topography and compensation points to one of the 
second group of hypotheses, to a support of the range by flotation, 
and to the conclusion that the growth of the support has been more 
rapid than that of the range. The primary problem then becomes, 
not as to how the Himalayas are supported at their actual height, 
but why they are not even loftier; in other words, the problem is 
carried one stage farther back, from the origin of the range to the 
origin of its ‘ root’. 
This result of the examination of the geodetic data simplifies 
the explanation of some difficult geological questions. It affords an 
easy explanation of the indications which are found in the interior of 
the Himalayas, and of other similar ranges, of simple vertical uplift 
without disturbance, and also of the manner in which the contorted 
and faulted strata, the disturbance of which must have taken place 
under the pressure of some thousands of feet of rock, have been 
brought up to a level where they are exposed to denudation and 
their structure revealed; but it brings us very little nearer to an 
explanation of the ultimate origin of the range. It is a distinct step 
forward in illustration of the mechanism of the production of 
mountain ranges of the type of the Himalayas and the Alps, but we 
are as far as ever from an understanding of the power by which this 
mechanism is driven. 
ANNIVERSARY MEETING. 
5. February 18, 1916.—Dr. A. Smith Woodward, F.R.S., President, 
in the Chair. 
The following Awards of Medals and Funds have been made :— 
The Wollaston Medal is awarded to Dr. Alexander Petrovich 
Karpinsky, in recognition of his researches concerning the Mineral 
Structure of the Earth, especially in connexion with the Geology and 
Paleontology of Russia. 
The Murchison Medal, together with a sum of ten guineas from 
the Murchison Geological Fund, is awarded to Dr. Robert Kidston, 
in recognition of his valuable contributions to Geological Science, 
