Annotated record of the detailed examination of Mn deposits observed near the Median Rift Valley of the Atlantic Ocean

The data presented in this report is the result of investigations carried out by a number of laboratories on a suite of rocks dredged from the Mid - Atlantic Ridge at 45°N by F. Aura en to and K. S. Manchester during the three Bedford Institute cruises BI 19-66 Hudson, BI 22-68 Hudson, and BI 23-68 Theta.