At the height of the last ice age 20,000 years ago, the Delaware Bay did not exist. Then a warming trend, which continues to this day, joined the ancestral Delaware River with the ocean to create today’s Delaware Estuary. An estuary is a tidally flooded river valley. But 20,000 years ago, there were no tides yet to form it… "The ocean was 60 to 90 miles off the coast. Sea levels were about 390 feet lower back then," said Kenneth Miller, a marine geologist at Rutgers University.
/ / / Global Warming Led River, Ocean to Meet, Form Delaware Bay