USGS Catalog http://geoport.whoi.edu/thredds/bathy_catalog.html

Dataset Size Last Modified
     Folder  Digital Elevation Models   --
         Folder  Global/   --
         Folder  United States/   --
         Folder  Gulf of Maine/   --
         Folder  Other Regional/   --

THREDDS at USGS WHCMSC see Info
THREDDS Data Server [Version 4.6.15 - 2020-06-16T13:36:16-0600] Documentation