Subject to valid existing rights the following-described lands, in addition to the lands established as the Isle Royale National Park pursuant to sections 408 to 408b of this title, are made a part of the park:

(a) Passage Island, containing approximately one hundred and eighty-two acres, located in sections 3, 4, and 9, township 67 north, range 32 west, in Keweenaw County, Michigan: Provided, That the Secretary of the Navy shall retain control and jurisdiction over the following portions of the Island for lighthouse and boathouse purposes:

(1) All that part of Passage Island lying south of a true east and west line located four hundred and twenty-five feet true north of the center of the Passage Island Light containing approximately six and five-tenths acres.

(2) Beginning at the center of Passage Island Light, thence north thirty-three degrees fifty-two minutes east three thousand five hundred and fifteen feet to a point from which this description shall begin to measure, being the southwest corner of said boathouse site; thence north two hundred feet to a point being the northwest corner of said site; thence east one hundred and seventy-five feet more or less to the harbor shore; thence southeasterly following the harbor shore to a point on the shore being a point on the south boundary of the boathouse site; thence two hundred feet more or less west to the point of beginning, containing approximately seventy-eight one-hundredths acre.

(3) A right-of-way between the sites described in the preceding subparagraphs, to be defined by the Secretary of the Navy within a reasonable length of time after March 6, 1942.

(b) Gull Islands, containing approximately six acres, located in section 19, township 68 north, range 31 west, in Keweenaw County, Michigan.