In 2000, A. Scott Andres, a senior scientist and hydrologist with the Delaware Geological Survey, released findings that disclosed a unique formation at the swamp.
In geologic time, the swamp isn't that old.
It formed about 22,000 years ago in a fresh-water, cold-climate marsh and boreal forested swamp.
Organic matter started building up and a cold wind blew in silt, clay and sand from nearby dunes and surrounding high ground. More sediment washed in with runoff from streams.
Thin sheets of sand likely spread during times when the land thawed.
Conditions began to change about 10,000 years ago as the climate warmed, forming a temperate-forested swamp, bog and flood plain.
There was more erosion and movement of organic-rich sediment to the fresh-water swamp. Today, it's considered the northernmost Southern forest on the East Coast.