The Mississippian Borden Formation is a mapped bedrock unit in a state that was originally part of what other state?
Borden Formation: The Mississippian Borden Formation is a mapped bedrock unit in Kentucky, Indiana, Illinois, Ohio, West Virginia, and Tennessee. Kentucky: Kentucky ( , ), officially the Commonwealth of Kentucky, is a state located in the east south-central region of the United States. Kentucky:  Originally a part of Virginia, in 1792 Kentucky became the 15th state to join the Union.
Virginia