Geology & Natural History

Remains of at least seven mammoths, probably from a meat cache dating back more than 11,000 years, were found when the Colby Mammoth site east of Worland, Wyo., was excavated by a crew under Wyoming State Archaeologist George Frison in the 1970s.

Prospectors first struck oil in the Salt Creek Oil Field in northern Natrona County, Wyo. late in the 1880s. The first gusher came in in 1908. The subsequent boom lasted until the late 1920s, peaking in 1923, when the field produced more than 35 million barrels of oil. Tom Wall, who went to work in the field in 1917, stayed for decades and in the 1970s wrote out his memories of life in the oil patch through boom and bust. After 125 years and thanks to new technologies, the Salt Creek Field continues to produce today.

Anchor Dam was built in the 1950s on upper Owl Creek in Wyoming’s Bighorn Basin. The bedrock under the reservoir site is porous, and the reservoir has never held much water. The U.S. Bureau of Reclamation more than doubled its initial costs with subsequent mitigation efforts, which proved unsuccessful. The dam stands today high above a small pool of water.

Alcova Dam, a Bureau of Reclamation project, was completed in 1937. The reservoir opened in 1938 and a power plant was completed in 1955. The $20 million dam project didn’t achieve the high expectations of immense wealth that were forecast at the time of its inception, but continues to provide irrigation water for farmers and ranchers and generates hydropower for the area. Alcova Reservoir offers fishing, boating, camping and swimming opportunities for visitors.