The formation of the limestone rocks near Cherra gives rise to a curious phenomenon in the disappearance of streams in their hollows. Sometimes a river vanishes in a cleft beneath a high cliff, sometimes falls headlong into deep circular hollow and is lost to view, reminding one of the gardens of Cambalu,
“Where Alp the sacred river ran
By caverns measureless to man
Down to sunless sea.”
There are at least four such instances in the immediate neighbourhood of Cherra.
Caves are common, as might be expected. In that a little to the east of Pundua, at a trifling height above the plains, in company with two friends from Cherra, I penetrated 1300 paces, without fatigue or difficulty, and others have, I believe, gone much further. We were compelled to retreat only by deficiency of oil. Here, says the tradition, a great army entered, bound for the invasion of China, and were heard no more.