(a)  Pre-existing rights and permits

The enactment of this subchapter shall not affect adversely any valid rights heretofore existing, or any valid permits heretofore issued, within or relating to areas authorized for inclusion in the park.

(b)  Issuance of permits by Secretary for use of park lands and utility, highway, and railway crossings

Other uses of park lands, and utility, highway, and railway crossings, may be authorized under permit by the Secretary, if such uses and crossings are not in conflict with the purposes of the park and are in accord with any requirements found necessary to preserve park values.

(c)  Crossing by foot at designated locations; purposes; conduct

Authority is hereby granted for individuals to cross the park by foot at locations designated by the Secretary for the purpose of gaining access to the Potomac River or to non-Federal lands for hunting purposes: Provided, That while such individuals are within the boundaries of the park firearms shall be unloaded, bows unstrung, and dogs on leash.