For generations, indigenous Wabanaki people hunted, caught fish, and harvested clams and oysters along the coast of what’s now called Maine. And they left behind middens — heaps of shells — that sometimes contain tools, ceramic shards and bones of animals.

Alice Kelley and Bonnie Newsom are in a race against time and tides to document the cultural and paleoenvironmental information contained in the shell heaps before they’re swept out to sea.