[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 interest felt in it must be deepened by the fact, that, in all probability it is the only one in southern India.
The action, however, even of a large crater like this must have been comparatively limited, other vents and fissures, which have left no permanent mark of their existence must have given exit to those vast sheeted masses of porous and solid rocks constituting the trappeau plateau of the Deccan. This plateau over lying primary and secondary rocks to depths varying from a few feet to 300 probably, covered 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 79° 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 indicate the persistence of igneous action. Taking Loonar as a centre, and with a radius of 150 or 200 miles, the quarter circle extending 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.
