| Orogeny and Metamorphism:
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| Sedimentary deposits:
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| Atlantic Coastal Plain (120 million years ago to now, Cretaceous to Recent):
Deposition of mostly unconsolidated sands and gravels all along Atlantic coast
from New England to Florida (incl. Long Island); mostly low elevation terrain.
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Alleghenian Orogeny (about 300-250 million years ago, Carboniferous
to Permian, a late phase of Appalachian Orogeny):
Formation of Appalachian Mountain Chain from Pennsylvania
south to Alabama
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| Allegheny Plateau (from about 410-360 million years ago, Devonian period):
Sedimentary deposits (mostly flat, agricultural land) in central and western
N.Y. State south of 43oN Latitude, continuing south into Pennsylvania.
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| Interior Lowlands (about 480-410 million years ago, Ordovician to Silurian):
Sedimentary deposits (mostly flat, agricultural land) in central and western
N.Y. State near Lake Ontario, also north and south of Adirondacks.
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Taconic Orogeny (about 550 to 440 million years ago, Cambrian
to Ordovician, an early phase of Appalachian Orogeny):
Widespread metamorphism; formation of Taconic Mountains
in eastern N.Y. State, also most geological formations of
interior New England, incl. Green Mountains of Vermont, etc.
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Grenville Orogeny (about 1.3 to 1.0 billion years ago, mid-Proterozoic):
Formation of Adirondack Mountains in N.Y. and Laurentian
(or Laurentide) Mountains in Canada.
Very intense metamorphism over a very long time. Mountainous
terrain has lasted ever since.
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