Digital collections

Echometre record obtained by the French liner S.S. De Grasse when crossingover the head of a canyon on Georges Bank. Such records reinforced the viewthat vessels could navigate by using bathymetry. Accordingly, the United StatesCoast and Geodetic Survey embarked on a project to map the continental slopesand shelves to help guide mariners into United States ports. (Image credit: NOAA Central Library Historical Collection)