Abstract
Fifteen beach-sand samples were taken from points along the shore of Lake Michigan in Illinois, Indiana, and southwestern Michigan. These are described petrographically, and their variations in textural composition, carbonate content, heavy mineral percentage, and heavy mineral frequencies are described and shown graphically. Two unlike series of beach sands are indicated by these characteristics, each of which shows progressions from one sample to the next. One series characterizes the western beaches, the other the eastern beaches. As the sands shift southward from the till cliffs, their principal source, they undergo regular and consistent changes tending to reduce them to a more stable end-type, the present deposits of the Indiana beaches. The factors controlling these sedimentation-variations' are briefly reviewed.
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