Ancient Shores

by Jack McDevitt

A vast lake, known as Lake Agassiz, covered much of North Dakota, Manitoba and Minnesota during prehistoric times.

The story begins when farmer Tom Lasker and his son, Will, uncover a seemingly brand new yacht. Found on a landlocked farm, it draws tourists to the area. Max Collingswood, a friend of Tom's, tries to help discover the origins of the boat. Collingswood enlists April Cannon, a worker at a chemical lab who discovers that the yacht is made of an unknown material. In fact, it is a fiberglass-like material with an impossible atomic number (161).

Collingswood and Cannon discover something else on a nearby ridge which is part of a Sioux reservation. The Sioux assist in its excavation and examination. It turns out to be a green glassy roundhouse-like structure, made from the same material.

Eventually, they gain access to it, revealing a dock for the sailboat, but no entrance for it. The discovery that the structure contains the means to access other sites not on Earth sets off a struggle between the Government and the Reservation for control of it.