Answer:
The purpose of a map scale is to help the user to know the distance between 2 or more cities or geographical elements.
18 States - North Carolina, Ohio, Alabama, Connecticut, New York, Georgia, Kentucky, Maine, Maryland, Massachusetts, Tennessee, New Jersey, New Hampshire, Pennsylvania, South Carolina, Vermont, West Virginia, and Virginia. The Appalachain mountains are found in these states, so it is only logical sediments could be found inside of them.