 NM 56/52, 12/29/1956; REPORTS THE EXISTENCE OF AN OBSTRUCTION (PA) EAST OF MERCER ISLAND IN LAT. 47/34/16 N, LON. 122/11/43 W. (NAD27), (ENTERED 01/04 BY KRW).

Search area partially investigated with SWMB (Reson 8125). Several insignificant possible