Editing Hudson River (section)

==Geology==
[[File:Cole_Thomas_Sunny_Morning_on_the_Hudson_River_1827.jpg|alt=View from a mountain top down the Hudson|thumb|[[Thomas Cole]], ''Sunny Morning on the Hudson River,'' 1827]]
The Hudson is sometimes called, in geological terms, a [[Estuary#Classification based on geomorphology|drowned river]]. The rising [[sea level]]s after the retreat of the [[Wisconsin glaciation]], the most recent [[Quaternary glaciation|ice age]], have resulted in a [[Fjord|marine incursion]] that drowned the coastal plain and brought salt water well above the mouth of the river. The deeply eroded old riverbed beyond the current shoreline, [[Hudson Canyon]], is a rich fishing area. The former riverbed is clearly delineated beneath the waters of the Atlantic Ocean, extending to the edge of the [[continental shelf]].<ref name="HudsonRiverEstuary"/> As a result of the glaciation and the [[sea level rise|rising sea levels]], the lower half of the river is now a [[tidal estuary]] that occupies the Hudson Fjord. The fjord is estimated to have formed between 26,000 and 13,300 years ago.<ref name="Fjord"/>

Along the river, the Palisades are of [[metamorphic]] [[basalt]], or [[diabase]]s, the Highlands are primarily [[granite]] and [[gneiss]] with [[intrusion]]s, and from Beacon to Albany, [[shale]]s and [[limestone]]s, or mainly [[sedimentary rock]].<ref name="Guide"/>{{rp|13}}

The Narrows were most likely formed about 6,000 years ago at the end of the last ice age. Previously, Staten Island and [[Long Island]] were connected, preventing the Hudson River from terminating via the Narrows. At that time, the Hudson River emptied into the Atlantic Ocean through a more westerly course through parts of present-day northern New Jersey, along the eastern side of the [[Watchung Mountains]] to [[Bound Brook, New Jersey]] and then on into the Atlantic Ocean via [[Raritan Bay]]. A buildup of water in the Upper New York Bay eventually allowed the Hudson River to break through previous land mass that was connecting Staten Island and Brooklyn to form the Narrows as it exists today. This allowed the Hudson River to find a shorter route to the Atlantic Ocean via its present course between New Jersey and New York City.<ref name="AutoYG-4"/>

Suspended sediments, mainly consisting of clays eroded from glacial deposits and organic particles, can be found in abundance in the river. The Hudson has a relatively short history of erosion, so it does not have a large depositional plain near its mouth. This lack of significant deposits near the river mouth differs from most other American estuaries. Around New York Harbor, sediment also flows into the estuary from the ocean when the current is flowing north.<ref name="RP"/>