This habitat occurs on gravelly deltas and along relatively steep shores in inlets. The substratum is a mix of gravel, sand, mud and in some areas, cobbles. The energy level is high enough to prevent siltation, but low enough not to scour the rooted salt marsh vegetation that occurs in upper littoral zones. Interstitial soil salinities range from meso- to polyhaline. These areas are sparsely vegetated. Gravelling deltas to improve oyster culture has been a practice in the Puget Trough for a long time, so many of these habitats are enhanced or artificial.
The vascular plant Glaux maritima (saltwort) is the primary salt marsh species in this habitat. The pickleweed Salicornia virginica is the co-diagnostic species in polyhaline environments. Pockets of two other dominant species occur in microhabitats of different salinities: the sedge Carex lyngbyei has a broad range, but tends to be the co-diagnostic species for mesohaline environments. Those habitats where freshwater seeps over the surface are oligohaline. The sole diagnostic plant species is the umbel Lilaeopsis occidentalis.
The brown rockweed Fucus sp. and the vascular plant Plantago maritima.
Quilcene Bay, Dosewallips River Delta, Duckabush River Delta, Hamma Hamma River Delta, Skokomish River Delta, Stavis Bay, Priest Point Park.