Saginaw Bay, a southwest extension of Lake Huron, is a shallow-water derivative of Pleistocene Lake Saginaw. Sixty-one bottom samples were collected on a semigrid pattern and analyzed physically. Sediments range in size from large pebbles to clay. Medium- to fine-grained quartz sand is common. Currents and wave action are primarily responsible for both median diameter and sorting distribution patterns. Heavy minerals are abundant locally in shallow-water areas subject to prevailing currents, and locally are concentrated by shape. Increased organic content is correlative with quiet water environments. Sedimentary criteria suitable for other than local correlations cannot be recognized in this physically heterogeneous shallow body of water.