Slowly and methodically he worked up the crevice, knocking off certain sharp points of rock, and knowing all the while what would probably happen to him if he were overheard.
He was not discovered, however.

When he laid elbows on the upper level of the rim and pulled himself up, his coat was on his back where it belonged, and even Barney could have followed him.

Yet the top showed no evidence of a widening of the fissure.

The bushy junipers hid him completely while he reconnoitred and considered what he should do.
Because the place was close and the invisible call was strong, Casey went first to the rock hut, circled it carefully and found that it was exactly what it had seemed at first sight; a hidden place with no evident opening save that high, small window under the eaves.

There was no sign of pathway leading to it, no trace of life outside its wall.