An intergrade results from two of the same species, but different sub species mate. For example: My Manouria emys phayreii male bred my Manouria emys emys female and the resultant babies are called "intergrade".
Not sure what Ryan's asking, but Terrapene carolina carolina is found on the east coast. You would also have to include T.c.bauri as being on the east coast also just in Florida.