This article telling the history of the
Old Bass River Road, South Dennis, Cape Cod notes:
Derick's 1725 map places a windmill over there on Old Chatham Road. "It
was owned by Hattil Kelley, a descendent of David Kelley, who settled that
land back in the 1600s," Derick says. "The windmill is not shown on the
1830s map. No one knows why it disappeared."