Weekly topographic profile measurements across a southward migrating recurved‐spit complex throughout a summer period have revealed three different mechanisms of berm development, each reflected by a distinctive sedimentary sequence. Each mechanism dominates berm widening along certain sections of the active spit with transition zones separating each one. Along the straight beach sections where a net longshore transport is well developed, sand accumulates at the distal high‐tide swash mark during neap tide. These sandy accumulations are neap berms which are later redistributed over the main berm by swash occurring at spring high water. The main berm grows vertically and horizontally as a result. To the south, along the middle portion of the recurved spit, swash bars or ridge‐and‐runnel systems actively develop, migrate, and weld onto the established berms. This is the second method of berm widening and results from an excess of sand carried into this portion of the spit due to the steadily decreasing transport of the longshore current system. Berm‐ridges develop along the southernmost portion of the active recurved spit and represent the third and most rapid form of beach progradation. Wide, broad swash bars build nearly up to the spring high tide level. At neap high tide, the swash cannot extend over this feature. Wave energy is expended on the seaward margin of the swash bar initially developing a low‐angle beach face. Rapidly, this beach face steepens and a new berm (beach face and berm top) is developed on top of the swash bar. This berm structure still retains much of its swash bar or ridge appearance, hence the term‘berm‐ridge'. Numerous trenches dug into the beach provide data to model the distribution of primary sedimentary structures in recurved spits. Berm‐ridges are the most important features along rapidly accreting spits, and structures associated with these features are volumetrically the most significant. Berm‐ridges also develop arcuate, vegetated ridges separated by low lying, marsh‐infilled swales. These features are commonly seen within barrier islands and designate former inlets.

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Seismic reflection surveys of 8 of the 11 Finger Lakes of central New York Statehave documented the deep (as much as 306 m below sea level) glacial scour of these lake basins and their subsequent infill by thick (up to 270 m) unconsolidated sediment. Drill data indicate that sediment infill occurred rapidly during a short interval between ~14,400 and 13,900 14C yr ago, coeval with Heinrich event H-1 when large volumes of icebergs and meltwater were discharged into the North Atlantic during an unstable phase of the Laurentide ice sheet.Six acoustically defined depositional sequences beneath the lakes, correlated with drillcore and piston core samples, record the infill history of the Finger Lakes during the late Wisconsin. Depositional sequence I is equivalent to thick, water-laid sands and gravels of the Valley Heads moraine deposited ~14.4 ka. During retreat of the ice margin from its Valley Heads position, subglacial meltwaters transported large volumes of fine-grained sediment into the Finger Lake basins (sequences II and III). Sequence IV records a phase of high-level proglacial lakes when ice blocked northern outlets of the Finger Lakes and fine-grained sediments continued to be transported into the basins from the north. An abrupt drop of proglacial lake levels and a drainage reversal is recorded by sequence V when sediments first began to enter the Finger Lakes from the south following retreat of the ice margin past the northern outlets of the lakes. The well-known modern glens and waterfalls of the Finger Lakes region formed at this time when lateral streams adjusted to dramatically lowered

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