348 Dr. Adam on the Geology of the Banks of the Ganges. 
on end, or lying with their long axes in a horizontal position, and 
piled one above the other to the height of 100 or 150 feet in the 
most elevated isles, the summit being terminated by a block more 
conical and pointed than the rest. The structure of these rocks 
is different at different parts of the islets ; but their general consti- 
tution appears essentially the same, varying only in the proportion 
of ingredients, the arrangement which these relatively observe, and 
the more or less sound and undecomposed condition of each. 
Granite is most generally met with ; it is found in huge blocks 
lying prostrate at the water’s edge, or rising w T ith bold pointed termi- 
nations to the summit of the island. Mica slate, like the former, is 
found in masses, but not of the same size, nor reaching so high ; 
it may be considered as that rock in the first stage of disintegration. 
Gneiss and mica slate are found at the lower part of the island ; and 
in a similar situation granite appears to graduate into mica slate. 
Between many of the blocks of granite reaching to about one third 
of the elevation, but chiefly at the water’s edge, I found a conglo- 
merate consisting of quartz and felspar, with a calcareous cement. 
In the lowermost isle there appears some difference in the 
arrangement of the ingredients of the rocks. This islet rises like 
the other two, boldly from the stream, and ranks second in point 
of height. Granite is equally abundant in this islet as in the other 
two, and occupies a similar situation. Granite, gneiss, and mica 
slate, occur in detached masses at the bottom of the islet. 
Similar to the elevations at Sicligully, Pointy, and Vidasrong, 
is that of Juangira, between Bhaugulpore and Monghyr. There 
is a pile of rocks consisting of granite with hornblende, about 
twenty feet high at the water’s edge, and the same rock occasionally 
projects from under the surface at different parts of the declivity, 
and appears to constitute the whole of the mount. It does not 
