he looked down at the broad sweep of the river , his gaze following the flow of the water as it rounded the bend and flowed swiftly on to his right , past the cafe perched on the pontoon , which was floating gently on the high tide , past the little quay with its boats moored up for the night , and on down the broad sweep of the river until it disappeared from view behind raven 's rock , a jagged outcrop that towered over the river .