98 
Records of llie Geological Survey of India. 
[vol. VII. 
editorial comment; the more so, as it affords a most instructive illustration of what threatens to 
become a very serious stumbling-block in geology, involving, as it does, the ignoring, abandon¬ 
ment, or even the inversion of the fundamental principle of the science. The evil indicated is, 
the blind adoption, or application, of the homotaxeous method in the classification and nomencla¬ 
ture of formations. 
Glacial phenomena, and the ‘ glacial period,’ having been lately very prominently under dis¬ 
cussion, it will astonish many that in a paper treating specially of the former enormous extension 
of the Himalayan glaciers, no mention should be made of the possible connection of this fact 
with * the glacial period ’; the sole cause assigned for the case of the Himalaya being a supposed 
greater elevation of from 12,000 to 15,000 feet. The local time assigned by Mr. Theobald for the 
Himalayan glacial period may be correct; there is no doubt of its being posterior to the disturb¬ 
ance of the IS'Allan group, and to the excavation in it of the existing drainage system; and the 
reason given for its being anterior to the Sivalilc group (as properly restricted by Mr. Theobald) 
is at least plausible. But here the fallacy steps in : the Sivalik formation is ‘ pliocene ’; the 
* glacial period ’ is * post pliocene ’; it is therefore needless to consider the relation of the latter 
with the prepliocene glacial period of the Himalaya, as well attempt to identify it with our 
Talchir (palaeozoic) glacial period. 
It is enough to state the case, to show the danger of it. Palmontologists are cutting them¬ 
selves adrift in loosening their hold upon the chain of physical causation. Are they in a condition 
to say that oven the Sivalik fauna (as restricted) could not be contemporaneous with the post- 
tertiaries of Europe, as is implied in the above argument ? 
It is plain that the possible, not to say probable, connexion of the glacial periods here and 
in Europe offers an incomparable means of fixing the contemporaneity or correspondence of the 
extinct faunas of such distant regions. The importance of this possibility will not be lost sight 
of.— Editor. 
On the Building and Ornamental Stones of India, by V. Ball, m. a., Geological 
Survey of India. 
In the year 1871, when at home on leave, my friend Professor Hull, Director of the 
Geological Survey of Ireland, informed me of his intention of bringing oat a work on Build¬ 
ing and Ornamental Stones, and invited my assistance in reference to the portion of 
it treating of India. Fortunately my promise of assistance was made conditionally upon 
my having leisure sufficient to hunt up all available authorities on the subject, as since 1871 
up to the present time (April 1874), I have been almost constantly on the move, and during 
the short periods I have spent in Calcutta my time has been taken up by other more pressing 
occupations, so that I have found it utterly impossible to attempt to do anything like justice 
to the subject. 
Professor Hull’s book having been published in 1872, the present notes are printed in 
the Records as an instalment of what may hereafter be written. In a country covering 
so large an area as India, and where, in spite of the comparatively little use made of stones in 
modern British buildings, building stones have been employed for a long period of time 
by the natives, ample material exists for a very much more extensive account than the pre¬ 
sent. My chief difficulty has been to compress the principal facts within the limits available 
for the purpose. 
By giving full references to the principal authorities on the subject, the reader is 
placed in possession of a means of acquiring fuller details than there is room for in the 
present account. 
