New York and New England

Introduction

The Atlantic Ocean coast of the United States north of 40°30′ N is crossed by two important physiographic boundaries. The first is the limit of the coastal plain, a thick sequence of unconsolidated or semi-consolidated Tertiary formations that form a seaward thickening wedge down the eastern seaboard. Long Island (New York State) is the northern limit of this feature, the boundary running south of Staten Island, through The Narrows, up the East River along the east side of Manhattan, down Long Island Sound and out under Block Island, Martha’s Vineyard and Nantucket Island. Some Pliocene sediment, mostly glacially reworked, underlie Cape Cod. Hardly any of this material outcrops, being covered with glacial sediment. Staten Island, to the north of this boundary, is underlain by Triassic and Palaeozoic formations. North of Long Island, New York State, the coastline is principally composed of consolidated bedrock primarily of Cambrian and Ordovician age in the southern reaches...