Examples from the Web for rimrock
On either side were brownish red jagged peaks and rimrock faces, specked with snow.
The rimrock and the gravels above and below it constitute the Rattlesnake Formation.The Geologic Setting of the John Day Country|Thomas Prence Thayer
We followed along the ledge around the rimrock until we came to a little pass through.
One after another they leaped over the edge of the rimrock until most of the flock was destroyed.The Story of Wool|Sara Ware Bassett