Missoula, MontanaDecember 1956

In December 1956, a man in Martinsdale, Montana wrote to the Air Force claiming he had found an unusual object that contained a self-powered unit activated by an unknown mineral. He believed it might be part of a spacecraft. The Air Force asked local investigators to track him down and examine his discovery.

The investigators found that the man had moved to Missoula by the time they arrived. They interviewed three people in Martinsdale who had seen the object: a Post Office employee, an Assistant Postmistress, and a hotel and cafe owner. All three described it the same way: a black-gray rock about 10 inches long, 7 to 8 inches wide, and 2 inches thick, with a curved shape like a saucer (concave on one side, convex on the other). One small fragment had broken off. Everyone who saw it believed it was simply an unusual shaped rock, nothing more.

The investigators asked a geologist from the U.S. Geological Survey about the Martinsdale area. The geologist explained that lava rocks are extremely common there. The Castle Mountains and Crazy Mountains, both near Martinsdale, contain lava formations. Wind and water have scattered lava fragments across the landscape for thousands of years. The geologist showed samples of lava rock that matched the description perfectly, including small holes created by gases when the lava was molten. The object was almost certainly a piece of lava rock, he said.

The Air Force investigator concluded the object was probably a lava fragment or rock from a local geological formation. He noted it seemed unlikely that a spacecraft component would be mistaken for a rock by many people in a small ranching community where residents are familiar with mechanical objects and spread news quickly by word of mouth. He suggested the man may have genuinely believed his find was unusual after someone jokingly called it a flying saucer. The approving officer agreed, concluding it was probably just a misidentified common rock.

The complete case file, held by the National Archives, is reproduced below across 24 pages.