Pioneering, Scottish nineteenth century studies of sedimentary processes in fluvial, estuarine and coastal environments

Nineteenth century studies of Earth surface processes in Scotland represent pioneering work that remains of contemporary significance. Four examples, from almost forgotten studies in contrasting environments, illustrate the contributions made and their legacy. The calculations of the sediment yields of the River Nith, in Dumfriesshire, and the Reisgill Burn, in Caithness, as measures of the lowering of their respective drainage basins (Geikie 1868a), are two of the earliest attempts to quantify denudation rates, studies of which have great significance to this day. Experimental observations by Robertson (1874) showed that increased salinity promotes the 'precipitation' of clays where such river-borne particles meet saline waters and provided the fundamental basis for numerous modern studies of the behaviour of fine grained sediments in estuarine and deltaic environments. Still more fundamental, and underpinning our understanding of estuarine water and sediment dynamics and the classification of such environments, are the measurements by Fleming (1816) of the salt content of the Tay Estuary at differing depths and stages of the tide which, for the first time, identified the salinity stratification of estuarine waters. At Dunbar, in East Lothian, Black's (1877a) observations of beach pebble shape and patterns of migration provided early insights into the relative energies of swash and backwash, and the controls on the longshore migration of pebbles, but also included the first attempt at numerical classification of pebble shape as an estimate of the frictional forces acting on particles.