It’s a box turtle. Presumably either the eastern box turtle, Terrapene carolina carolina, or possibly a Florida box turrtle, Terrapene carolina bauri.
Here’s a size comparison:
I put him back where I found him, and a bit later he had crawled off into the le aves.
Pictures by Gretchen Quarterman, 5 June 2011, Lowndes County, Georgia.
-jsq
Short Link: