Geologically speaking, Long Island is quite young. This
22,000 year old mound of sediment was created when the last southern most
ice sheet retreated leaving behind all the rocks, sand and clay it pushed ahead of it. The
sea level began to rise around this mound of glacial
till resulting in the
elongate island you see today.
Evidence of the
terminal moraine are the hills that are oriented in an
east-
west fasion beginning in
Bay Ridge,
Brooklyn and run through central Long Island and into the
Atlantic Ocean near
Montauk Point. North of these hills are more east-west trending ones showing where
recessional moraines formed while the
ice sheets slowly retreated.