A study of some of the physical, chemical, and biological properties of the sediments has been made at 29 offshore stations in a 15-square-mile area of Lake Superior, near Silver Bay, Minnesota. Color changes in the sediments are believed to be due to the state of oxidation and reduction of the iron oxides. Textural variations are possibly in part caused by turbidity currents resulting from either sublacustrine mud slides or rivers during flood stages or both. Two biofacies of the sediments occur, based on (1) diatoms in offshore areas and (2) oligochaetes and malacostracans in nearer-shore areas. The bituminous fractions of the sediments are small in total but carry relatively more hydrocarbons and less asphalts than eutrophic lake sediments of central Minnesota.