Before the first Dutch colonists sailed through the Narrows into New York Harbor, Manhattan was still what the Lenape, who had already lived here for centuries, called Mannahatta. Times Square was a forest with a beaver pond. The Jacob K. Javits Federal Building, at Foley Square, was the site of an ancient mound of oyster middens.

Eric W. Sanderson is a senior conservation ecologist for the Wildlife Conservation Society, based at the Bronx Zoo. In 2009 he published “Mannahatta: A Natural History of New York City.” The book geolocated old maps onto the modern city to reimagine a cornucopia of hills, beaches, fields and ponds.

This is the latest in a series of (edited, condensed) virtual walks with architects and others. I spoke with Mr. Sanderson by phone. Our “stroll” explored Lower Manhattan. We “met” where the Staten Island Ferry docks at Whitehall Terminal... [+]