“ They consist of three principal ridges, which are entirely covered at high water. The celebrated lighthouse on one of these rocks was begun in 1756 and finished in 1759. Its tower is 68 ft. high, and is surmounted by a lantern which is furnished with 16 powerful argand burners, with parabolic reflectors of silvered copper. The first lighthouse on these rocks was built in 1696-'9, of stone and timber. ”