This is wonderful:
The aim of the Mannahatta Project is to reconstruct the ecology of Manhattan when Henry Hudson first sailed by in 1609 and compare it to what we know of the island today. The Mannahatta Project will help us to understand, down to the level of one city block, where in Manhattan streams once flowed or where American Chestnuts may have grown, where black bears once marked territories, and where the Lenape fished and hunted. Most history books dispense of the pre-European history of New York in only a few pages. However, with new methods in geographic analysis and the help of a remarkable 18th-century map, we will discover a new aspect of New York culture, the environmental foundation of the city.
Great pictures here