Co-op City is built on infilled marshland. Years before the arrival of the Dutch settlers, the Siwanoy tribe harvested shellfish from the tidal flats of the Hutchinson River. The river gets its name from Anne Hutchinson, an excommunicated religious leader from Massachusetts who, along with six of her children, was massacred by the Siwanoy, casualties of an ill-advised war started by then Director-General of New Netherland, William Kieft. If you are so inclined, you can visit the site of the massacre, Split Rock, where, as legend goes, Anne and her daughter Susanna unsuccessfully tried to hide during the Siwanoy attack. The rock itself is located on a triangle between the New England Thruway and the Hutchinson River Parkway. There used to be a plaque.