Which preposition to use with cleuch

in Occurrences 1%

But I ha' just been speerin the forester aboot the tod (fox), an' he gars me gang owr the muir to Ettric Forest, an' leuk in a cleuch in a rock there is there, an' I shall find the half-peckit banes o' a joop o' mine that stray'd yestreen.

Which preposition to use with  cleuch