All of the land lying below high-water mark in the city of Georgetown at the foot of King Street on the Sampit River adjacent to certain lands conveyed by the city of Georgetown to the United States Government, or any department thereof, has been ceded to the United States Government or department thereof. The lands so ceded to the United States shall revert to the State when they cease to be used by the United States. There was reserved to this State in such cession the concurrent jurisdiction for the execution within such premises of all processes, civil and criminal, lawfully issued by the courts of this State and not incompatible with this cession.