he gave suddenly a queer , deep grunt , and jerked his hand ; laurence looked down and saw his face pressed open-mouthed into the rock , making a horrible , low , stifled sound , his hand clawing madly at the stone : clawing , and coming to shreds , there was white bone gleaming at the fingertips , and abruptly bailes flung out his arm and fell away , his bared teeth clenched and visible , for a brief moment .