State Stone: Limestone (1971)
Some of the most famous limestone in the world can be found in Southern Indiana. This is a good clue that fossils and caves are likely. Indiana’s Salem Limestone, named for the city of Salem was formed during the Mississippian Period more than 300 million years ago.
While ancient seas and geologic processes left limestone, exotic forests left coal. More bituminous coal occurs in Indiana than anywhere else in the nation, most of it in the Illinois Basin in southwestern Indiana.
Please note that rock collecting locations are always changing so be sure to check with the site owner for the most current information before going.
Dig safe, never go underground, and make sure to get permission from the landowner to search for and collect rocks.