OCT. — DEC. J85G.] 
The Natron Lake of Loonar. 
7 
[Further communication from Dr. Smith, accompanied by a plan and section 
of the Lake.] 
In the plan now submitted, the crateriform shape of the hollow 
is well seen, and if the opinion of some Geologists be correct, 
namely, that this hollow is the crater of an extinct volcano, the in- 
terest felt in it must be deepened by the fact, that, in all probabi- 
lity it is the only one in southern India. 
The action, however, even of a large erater like this must have 
been comparatively limited, 5)ther vents and fissures, which have 
left no permanent mark ^f the;r existence must have given exit 
to those vast sheeted masses of porous and solid rocks consti- 
tuting the trappean plateau of the Deccan. This plateau over 
lying primary and secondary Tocks to depths varying from a few 
feet to 300 probably, d^vered with a rich mantle of inexhaustible 
black soil, and capped here and there along its eastern indented 
edge with laterite patches, extends from 17<* to 27^^ N. L. and from 
72° 30' to 790 E. L. 
It may be interesting to remark, that at the South East angle 
of the plateau, the existence of numerous hot springs seems to in- 
dicate the persistence of igneous action. Taking Loonar as a cen- 
tre, and with a radius of 150 or 200 miles, the quarter circle ex- 
tending from the North East to the South East, will be found to 
include (a) the tepid spring of Beder, rising from the base of a 
laterite cliff; (b) the hot springs at Kair on the Pain Gunga (87® 
Bradley) and (c) the hot springs near Labbundee (102<» Bradley) 
lying in a North Easterly direction. 
