part 3.] Ball: Building and Ornamental Stones of India. 10i 
I.—Granite and Gneiss. 
Most of the so-called granite of India is a granitoid gneiss, a resultant of the excessive 
metamorphism of sedimentary rocks. To what extent true eruptive, igneous granite occurs 
in the peninsula is quite unknown. Granite, which from its physical relations one may 
venture to conclude is of truly igneous and eruptive character, is not however absent. But, 
as a rule, the physical relations accompanying exposures of perfectly unfoliated granites in the 
metamorphic ai-eas of India are not of a sufficiently definite character to enable one to assert 
with confidence the nature of the origin of those granites. There is no crucial test which 
can be applied to determine tbis question. Even microscopical examination of the minei-als 
is not now considered to afford in all cases an infallible guide. But even if it be, it is not 
of easy application, and cannot be made use of in the field. 
These remarks seem a necessary preface to the following account, as travellers and 
antiquarians, who have described buildings, have not often attempted to characterise, more 
than by some very general term, such as granite or sandstone, the materials of which those 
buildings have been constructed. 
The metamorphic rocks occupy a very considerable area in India. 
East of a line drawn from Eotasgarh on the Son through Umarkantak to Goa, the 
greater part of the country consists of metamorphic rocks. The younger rocks which do 
occur in that area are for the most part limited to comparatively inconsiderable basins, 
Metamorphic rocks, not to mention small exposures within the limits of the great basaltic 
flows of Western India, also occur in Bandelkaud, Each, the Garo and Kasia Bills, 
and in the Himalayas. Whether these all belong to the same age or not is a question of 
much difficulty and uncertainty. The probability is that they do not. lithologically there 
is sufficient general resemblance to justify their being all classed together in this account. 
The varieties of materials suited to building purposes are of course very numerous. 
There are those caused by structure and those due to composition. By the former character 
they are divisible into foliated and non-foliated. The simplest form of the latter is a binary 
compound of quartz and felspar, or pegmatite, sometimes appearing as graphic granite. 
Then there are the ternary compounds, consisting of the two minerals just mentioned, with 
the addition of mica, hornblende, or talc, which are known respectively as granite, syenite, 
and protogiue. Various modifications of these four varieties are produced by the presence of 
foreign minerals, such as, oligoclase, schorl, garnet, epidote, magnetic iron, &c. 
As building stones the dense crystalline unfoliated varieties are the most durable. The 
presence of garnets or magnetic iron is likely to be detrimental, as these minerals under the 
influence of the atmosphere are apt to disintegrate, and so mar the appearance, if they do 
not ultimately endanger the stability, of the edifices in which stone containing them is 
employed. 
I shall now endeavour to give some enumeration of the principal localities where these 
rocks have been used for the supply of building stones, and point out the features of the 
principal examples. 
In the alluvial tracts of Bengal ancient buildings of stone are of most uncommon 
occurrence. Towai'ds the west, however, in the rocky districts and on their borders, evidence 
is not wanting that the art of working in stone was practised whenever the material was 
available. In the Ganges close to Colgong there are several small hills which form islands 
in the present bed of the river. These hills consist of piled masses of a very compact grey 
granite, which in olden times used apparently to be resorted to for material for the construe- 
