This data set was acquired with a ship-based Atlas Hydrosweep DS Multibeam Sonar system during Maurice Ewing expedition EW9309 conducted in 1993 (Chief Scientist: Dr. Jean-Guy Schilling). These data files are of MBSystem Compatible format and include Acoustic Backscatter and Swath Bathymetry data that have not been processed. Data were acquired as part of the project(s): Rock Dredging and Geochemistry of the Mid-Atlantic Ridge from 41 Degrees South to 51 Degrees South, and funding was provided by NSF grant(s): OCE90-11741.