The Drowned Lands of the Wallkill supported a vast array of species, and were part of the migration paths for them.  Fossil evidence here is helping study the progression of species and the enigma of why some species died out.

Scientist Guy Robinson studies these remains for evidence:

Summary of Robinson article:
Paleoecologist Guy Robinson of Fordham University has studied evidence of mammoth and other big game hunts in the Black Dirt area.  He says that the evidence points to the idea that over hunting was a major cause of their extinction at the end of the Pleistocene era. Prior theories postulated that the extinction was due to climate change, that the warming of the earth caused this extinction., but now some scientists believe a major contributing factor was the action of man.
    Radiocarbon dating is not precise, but the fact that these extinctions occurred around the time that the first spear points are being found in North America; recent data has made it clear the last of the mammoths and other ‘megafauna’ had disappeared before the heat wave that ended the Pleistocene.
   Robinson believes that by tracking the arrival of the humans and studying the evidence of climate change, it can clarify why they disappeared.  He works with ancient pollen and flecks of charcoal he digs up in the Black Dirt.  Fossil spores of a fungus that grows on the dung of large herbivores shows that they disappear from the sedimentary record just before charcoal marks of large fires—which he contends were set by man.
He has found the stomach contents of some mastodons from orange county and using his microscope, he can tell what kinds of plants grew near Lake Fairchild thousands of years ago, like alder pollen. Studying the preserved pollen, he can learn about long extinct ecosystems and the shifting patterns of plant communities.
   He has found two dramatic shifts in the microfossil record.  First, the dung fungus disappears, then within a few hundred years, landscape fires increase tenfold.  In this Robinson sees that local populations of large grazing animals crashed when the first people arrive and found them to be easy prey.  Without the huge herbivores, fuel sources built up and fires lit by lightning and people burned larger and hotter than ever before.  There is no pollen shift during this time period, disproving the theory of climate change.