The data reveals at least three separate and overlapping paleofluvial drainages that trend parallel to and beneath the modern bathymetric low. The other drainages form the unconformable upper surfaces of strata traceable, in places, beneath adjacent shelf areas. The location of the HSV may be controlled by a valley-parallel fault trace that is partially obscured by the paleofluvial erosion. Lobate accretionary clinoforms are found where some lateral channels merge with the youngest paleo-Hudson drainage, marking bayhead deltas deposited during relative stillstands of the Flandrian transgression. The HSV sequence is capped by a Holocene marine unit that grades from sandy silt on the valley floor to gravelly sand on the flanks.
Deposits are only a few meters thick in interbasin areas.