Fort Rock

Fort Rock Oregon Geology and History Fort Rock is the remnant of a maar volcano or tuff ring, formed when rising basaltic magma encountered water and exploded violently. The exploded debris- called tuff-fell back to earth around the volcanic vent to form this steep-walled, fort-like ring. Over time, the basin filled with a shallow lake, which breached the south rim of the tuff ring and cut a terrace about 60 feet above the floor of the valley. A State Monument and a National Natural Landmark, Fort Rock is one of several maars in the area; other examples are Hole-in-the Ground, Table Rock, Flat Top, and Big Hole. Look ahead of you to the east for a view of Fort Rock in the distance. Caption #1: In 1938, archeaologist Luther Cressman found dozens of 9,000-10,000-year-old Fort Rock-style sagebrush sandals in nearby Fort Rock Cave. Caption #2: *13,000 years BP (before present): The earliest Fort Rock inhabitants were nomadic hunters of large and small game. *6,000 years BP: People lived in small shoreline houses; they ate fish, seeds, roots and game, and traded for shell beads from as far away as southern California and northern Mexico. *3,000 years BP: Increasing reliance on upland root crops caused local populations to move to village sites located nearer the foothills around the marshes. *As late as 150 years BP: Some villages remained occupied by the ancestors of today's Klamath Tribes, Confederated Tribes of the Warm Springs Reservation, and Burns Paiute Tribe. Caption #3: Rich in game, fish, and edible plants, the Fort Rock Basin has long played an important role in the lives of Native Americans. It's one of the earliest known occupied sites on the continent; evidence dates human settlement here as early as 13,000 years ago. Caption #4: Herds of Ice Age bison, camels, horses, and mammoths grazed the lands adjacent to ancient Fort Rock Lake; fish and waterfowl thrived along in its shoreline marshes. The lake reached its maximum height about 21,000 years ago; and as the climate warmed, the lake gradually disappeared.