20 Rev, O. Fisher on Deflexions 
of the Sivalik beds an inverted inclined plane, whose depth 
is three miles and length 230. If we apply the principle of 
general isostacy to half of the area we are dealing with, that 
Fig, 2. 
Modification of Mr. Oldham’s diagram to suit the present hypothesis. 
A oS ee 
See? ee 
Scale about 105 miles to an inch. 
. Slope of the Himalayas, including the marginal deposit C of 
Mr. Oldham’s diagram. 
Root of the same. 
Sivaliks undisturbed and covered by subsequent deposits. 
Sunken lower surface of the crust contributing to the general 
support of half the highlands according to Mr. Putnam’s 
theory. 
chm - 
is from the middle of the Tibetan plateau to the further edge 
of the alluvial deposit 230 miles from the foot of the slope, 
we find that the depth of the root of the plateau will be 
diminished by one mile and three tenths. The attractions of 
the visible masses and the crust will of course remain as 
before, but the negative attraction of the root will be dimin- 
ished by 0°045 of its amount, and by so much will the 
attraction towards the range at any station be approximately 
increased. This will raise the attraction of the plateau and 
slope with their roots 
at the foot of the slope to 18"°757, 
at 60 miles from the foot of the slope to 3-212, 
at 293 miles it will convert the deflexion of 0!"186 away 
from the range into one of 0-628 towards it. 
These are not the final results, because the deflexions due 
to the area of the Gangetic plain have yet to be considered 
and added to them. 
The estimates just made of the structure and dimensions 
of the Gangetic plain, assumed to be rectangular, and of the 
depression of the coast beneath it into the substratum, when 
submitted to calculation yield the following results. 
Where the plain abuts upon the foot of the Himalayan 
slope it will cause a deflexion of 5-009 towards it. 
At 60 miles from the foot of the slope there will be a 
deflexion of 1'°352 away from the range. 
At the extreme edge of the plain, where it abuts on the 
