394° Second Report on the Geology of Hyderabad, [Ave. 
Ton’s trigonometrical measurement within 19 feet. Colonel Lams- 
ToNn’s observatory being 10 feet high, and the house where the obser- 
vation was taken between 5 and 10 feet lower than the base of the - 
observatory, the agreement will be much closer. 
The outline of the basaltic trap hills is smooth and rather flattened 
with a few conical elevations in the range; or they consist of an accu- 
mulation of round hills with deep ravines intersecting and separating ' 
them. They are covered with long grass to their summits. Their | 
course is the same with the granite they cover, but it frequently hap- 
pens that no regular direction can be perceived. 
The sandstone country and rocks are flat, the sides of the hills 
steep, with extensive gaps in the course of their range, at times nearly 
reaching to their bases; their direction is N. W. and S. E. or nearly 
so, and it is probable that they extend over a considerable portion of 
the S. E. part of Gondwana. 
Rivers. 
The rivers of India, and particularly the Godaveri and Kistna, are 
subject to great variations in the quantity of their waters dependent on 
the periodical rains. The small rivers are nearly dry in the month of. 
May, and the channels of the larger contract to a fifth from their size in 
the middle of the rains. 
I before mentioned that the tributary streams take their rise near to 
each other, and pass through a country of nearly similar formation, viz. 
basaltic trap, and discharge their waters into the sea within 60:miles of. 
éach other by several mouths, which like those of the Nile or the Ganges 
run through adelta formed by their own alluvium. Their waters are much 
discoloured in the rains, and deposit on their banks and throughout the 
whole extent of the inundation, which takes place more or less every 
year, a thick layer of black alluvial soil, called by Europeans “< black 
cotton soil.” These banks vary from 50 to 30 feet in height, the 
latter being the usual height of those of the Kistna. About 50 miles 
from their embouchure they both pass through the chain of granitic 
mountains which extend from Gantur to Gondwana before men- 
tioned. 
' The pass of the Kistna at Bejwdra is much broader than that of the 
Goddveri at Pdpkonda. This may be the cause of the more extensive 
inundations of the latter, since its channel is contracted from a breadth 
of two and one’ mile to two furlongs by the lofty and precipitous sides 
of these mountains. This defile constitutes the S. E. boundary of His 
Highness’s dominions. Its extent from the last Nizam’s village to the 
hearest Company’s village is about ten miles, which space is uninhabited, 
