Flynn Creek crater, is an impact crater situated in Jackson County, approximately 8 km south of Gainesboro, Tennessee, USA. It was formed approximately 360 million years ago as a shallow, saucer-shaped crater, 3.8 km in diameter and about 150 m deep. A large central hill, highly deformed rim strata, and a breccia lens 40 m in thickness were produced during formation. Over 2 km of flat lying Middle and Upper Paleozoic limestone and dolomite were brecciated and mixed to a depth of 200 m, and at least half of the breccia was ejected from the crater. The remaining breccia contains fragments ranging in size from small grains to megabreccia blocks 100 m in length. Undisturbed strata lie 100 m below the original crater floor.^[1]

• http://en.wikipedia.org/wiki/Flynn Creek crater