Field map of line of soundings offshore from Cape Henlopen, Delaware Bay.In the far SE corner, the break in soundings from 85 fathoms to 145 fathoms isone of the earliest indications of the continental shelf break.
Date: 1847 ca.
Credit: NARA C&GS; Colllection
Location: Delaware, Offshore
Subject: Coast and Geodetic Survey
Subject: Archive Seafloor Mapping