Single-beam bathymetry data along with GPS navigation data was collected as part of the U.S. Geological Survey cruise A-1-93-YB. The cruise was conducted in Yakukat Bay, Alaska from August 21 to August 27, 1993. The chief scientists were Paul Carlson of the USGS Coastal and Marine Geology office in Menlo Park, CA and Ellen Cowan of Appalachian State University and Ross Powell of Northern Illinois University. The overall purpose of this study was to characterize seismic facies for interpreting past glacier behavior, especially during the Last Glacial Maximum (LGM). The geophysical source was a hull-mounted 12 kilohertz (kHz) bathymetry echosounder. These data are reformatted from space-delimited ASCII text files located in the Coastal and Marine Geology Program (CMGP) InfoBank field activity catalog at http://walrus.wr.usgs.gov/infobank/a/a193yb/html/a-1-93-yb.meta.html into MGD77T format provided by the NOAA's National Geophysical Data Center(NGDC). The MGD77T format includes a header (documentation) file (.h77t) and a data file (.m77t). More information regarding this format can be found in the publication listed in the Cross_reference section of this metadata file.