  L-346/53; SAN PABLO STRAIT-WRECK- LIGHTED BUOY DISCONTINUED.  BARGE WRECK- LIGHTED BUOY WR6 HAS BEEN DISCONTINUED.   APPROX. POSITION: 37°57'32"N 122°26'28"W (NAD27).  NOTE.- THE CORPS OF ENGINEERS ADVISES THAT THE AREA HAS BEEN SWEPT TO A DEPTH OF 50