Post-Miocene stratigraphic units on the coastal plain of southeastern Virginia consist of nearshore marine, beach, backbarrier, and fluvial facies. Electron-microscope studies of surface features on quartz grains from these stratigraphic units suggest origins which correlate closely with information obtained independently from stratigraphic studies.

Superposed surface features were used to establish the depositional history of sand grains affected by more than one environment. Relative ages of stratigraphic units were determined from degree of surface etching on quartz grains. The presence of surface features characteristic of glacial action has been used to differentiate Pleistocene from pre-Pleistocene stratigraphic units. The contact between beach and dune sand, as determined by electron microscopy, has been used, together with independent stratigraphic data, to determine the maximum elevations of Pleistocene sea levels associated with the stratigraphic units and morphologic features on the Virginia coastal plain.

This study shows a close correspondence between inferences based on electron-microscope studies of quartz-grain surface textures and independent data obtained from field studies of morphology and stratigraphic relations. The correlation suggests that electron-microscope studies may be useful in interpreting

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older sediments where morphology and sedimentary structures are less well preserved, and where the effects of weathering are more severe.

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