Samples were divided into two aliquots. The first aliquot was leached with an excess of 1 M acetic acid to remove calcium carbonate. CaCO3 contents of each sample were determined by analysis of these leach solutions for Ca by AAS. The second aliquot of each sample was attacked with a mixed acid-reducing agent [1 M hydroxylamine-HCl and 25% (v/v) acetic acid] following the procedure of Chester and Hughes (1967, doi:10.1016/0009-2541(67)90025-3). Data for CaCO3 contents are given for dry bulk sediments; other data are given on a carbonate-free basis.