'Clefts of the Rock' in the Bible

These [armies, like flies and bees] will all come and settle on the steep and rugged ravines and in the clefts of the rocks, and on all the thorn bushes and in all the watering places.

Who inflame yourselves [with lust in pagan rites] among the oaks (terebinth trees),Under every green and leafy tree,Who slaughter the children [in sacrifice] in the ravinesUnder the clefts of the rocks?