ON THE GEOLOGY 



such as is described in that theory, without covering the sand-stone also. 

 Its known effects on other rocks, which come in contact with it, are also 

 striking circumstances ; but as India possesses advantages over all other 

 countries in the investigation of this subject, it would be premature in- 

 deed to draw inferences before we are in possession of the facts, which 

 alone will enable us to arrive at a satisfactory conclusion. The thickness 

 of this formation we have it not in our power to obtain, as it is con- 

 stantly variable ; in the centre of India, it occupies the summits of the 

 highest mountains, and at Bombay, it descends to the level of the sea ; 

 it reposes indiscriminately upon every rock, from granite upwards, and it 

 is quite impossible to fix on any average : it is useful, however, to find 

 out the rock on which it reposes, and its inferior level in the tract under 

 examination ; thus, for instance, at Sugar, it reposes on sand-stone, and 

 its inferior line, in that district, is about 1350 feet above the sea, and as 

 this is also the superior limit of lias, it follows, that the trap of Sdgar is 

 unequivocally posterior to sand-stone, and may be either just previous 

 to, or contemporaneous with, or posterior to lias, the latter of which, I 

 apprehend, will be found to be the case. 



There are two kinds of basaltic rocks in the district of Jebelpur, 

 which are clearly distinct formations; the oldest variety is that which 

 penetrates the grayivacke stratum in the bed of the Nermada river, near 

 the village of Lamaita. This stratum, though not above fifty yards thick, 

 is intersected by innumerable green-stone veins and nodules, always run- 

 ning in the direction of the strata, and as they do not occur in any of 

 the adjoining formations, they must, I presume, be at least as old as 

 that rock ; the other basalt is an overlying rock, like that of Sdgar, but 

 it reposes on granite or gneiss, instead of sand-stone, and appears to con- 

 tain a greater proportion of aiigite. 



The 



