ABSTRACT

Seven beach sand samples were collected at mile intervals along Cedar Point spit on the south side of Lake Erie. Shape and roundness analyses were made on the light, carbonate-free fraction of the six size grades common to all samples. Sphericity declined slightly and roundness considerably in the direction of sand shift. The feldspar content, about 25 per cent, was unchanged.

Data obtained in this study and the published field and laboratory work on other sands, shows that simple abrasion cannot account for the observed trends. Water currents, sorting the sands of the beach in the down-current direction, carry the less spherical grains further than the more spherical, other things being equal, and since roundness was found to be closely correlated with sphericity, concomitant roundness decline takes place. The correlation of roundness and sphericity is the result of abrasion in earlier cycles of sedimentation.