Grand Canyon, near Williams Field (Arizona) — June 30, 1947 (0910)
A Navy lieutenant was flying at 9000 m toward the south when he saw two circular objects diving at “un- conceivable” speed. They were gray, about 3 m in diameter, and appeared to land 40 km south of the Grand Canyon. {Atic)
Source: Passport to Magonia
Case: 59