101 
Records of the Geological Survey of India. 
[vol. VII. 
The former, however, are not generally suited for building purposes,* and are therefore 
less used than trap, which, though sometimes difficult to cut, is, if well chosen, a most durable 
material, and is moreover susceptible of much delicate and artistic treatment. 
As might he anticipated in the Delean area, from the enormous thickness of these rocks 
which occur, the lithological varieties are numerous. These varieties are due both to differ¬ 
ences in mineral composition and degrees of compactness. 
With regard to the relative adaptability to building purposes of the various kinds of 
rock which are most commonly met with, Mr. Blanford remarks: “ None of the beds 
containing zeolites, interspersed in irregular strings and veins throughout the mass, are 
good. They are too soft, brittle, and liable to decompose. None of the ash beds are equal 
in strength, toughness, or resistance to the atmosphere to the solid basalts, and no rock 
of a red colour should ever be taken for building purposes. It is almost always decomposed. 
Amongst the very best beds are the porphyritic basalts, such as those which form so large a 
proportion of the rocks on the Thull Ghat.” 
Mr. Bell says:—“ The best I should consider to be the bluish-green basalt, which is very 
hard and heavy, having a specific-gravity about 3'0, and which rings like a metal on being 
struck.” 
Probably the first use to which the trap rock was put in India was in the manufacture 
of stone implements or celts, of which specimens are occasionally found, in some cases far 
removed from the places where the rocks occur. 
To a very early period must be referred that form of architecture which consisted in 
hollowing out and sculpturing the rock in situ into temples and dwelling places, of which 
we have magnificent examples in the caves of Adjanta, Ellora, and Elephanta. These caves 
contain sculptures and inscriptions indicative of their Buddhistical or early Brahminical 
origin. Several of these caves are assigned to a period from 200 to 150 years B. C. 
At Gya, according to General Cunningham, some of the Buddhistical rails are made of 
basalt, others being of granite and sandstone. 
Coming down to a more recent period, we find on the eastern side of India trap from 
the Rajmehal Hills made use of for lintels and door posts in Hindu temples, and not unfre- 
quently for the images contained inside. Trap used in this partial manner may be seen in 
many of the old buildings in the vicinity of Rajmehal and the ruined city of Gaur: occa¬ 
sionally, too, in temples in the Burdwan District. The black marble of many writers is pro¬ 
bably only this material. When covered by the native offerings of ghee, it is often, without 
doing what in the sight of the people would be regarded as desecration, impossible to make 
out the material of which the images are made. 
In the famous Black Pagoda at Pori trap is said to have been much used. This mate¬ 
rial was probably derived from dykes in the metamorphic rocks. 
In the Dekan and surrounding trap country this material has been used in the construc¬ 
tion of forts and native buildings of various kinds. 
One of the most magnificent works in trap is stated by Dr. Balfour to be an unfinished 
tomb of one of the Gwalior princes at Poona. 
Recently it has been extensively used in the construction of bridges and stations on the 
lines of railroad which traverse tho trap country, but I understand that from causes for 
which the stone is not altogether in fault, but rather the lime and workmanship, the work 
has not given complete satisfaction. 
An exception will be found noted on a following page. 
