A Mechanical Cause of the Lamination of Sandstone not hitherto noticed

Abstract

THE lamination of sedimentary rocks is usually attributed to the successive deposition of sediment of varying degrees of fineness or coarseness. Currents of water have a selective action on the materials that are swept along by them, by which grains of one size and weight are laid down at one time, and of another size and weight at another, Changes in the nature of the material in suspension also occur through which the deposit may be at different times more siliceous, argillaceous, or calcareous. This is doubtless in most cases a true explanation of the cause of lamination in rocks, but it is not a full one, nor does it account for stratification such as I am about to describe.