In order to commemorate the Civil War battles of Fredericksburg, Spotsylvania Court House, Wilderness, and Chancellorsville, including Salem Church, all located at or near Fredericksburg, Virginia, and to mark and preserve for historical purposes the breastworks, earthworks, gun emplacements, walls, or other defenses or shelters used by the armies in said battles, so far as the marking and preservation of the same are practicable, the land herein authorized to be acquired, or so much thereof as may be taken, and the highways and approaches herein authorized to be constructed, are declared to be a national military park to be known as the Fredericksburg and Spotsylvania County Battle Fields Memorial whenever the title to the same shall have been acquired by the United States, the said land so to be acquired being the land necessary for a park of the plan indicated on the index map sheet filed with the report of the Battle Field Commission appointed pursuant to an Act entitled "An Act to provide for the inspection of the battle fields in and around Fredericksburg and Spotsylvania Court House, Virginia," approved on the 7th day of June 1924, said index map sheet being referred to in said report, and particularly in the "Combined Plan—Antietam system," described in said report, the first of the plans mentioned in said report under the heading "Combined Plan—Antietam system" being the plan which is adopted, the said land herein authorized to be acquired being such land as the Secretary of the Interior may deem necessary to establish a park on the combined plan, Antietam system, above referred to, the particular boundaries of such land to be fixed by surveys made previous to the attempt to acquire the same, and authority is given to the Secretary of the Interior to acquire for the purposes of sections 425 to 425j of this title the land above mentioned, or so much thereof as he may deem necessary, together with all such existing breastworks, earthworks, gun emplacements, walls, defenses, shelters, or other historical points as the Secretary of the Interior may deem necessary, whether shown on said index map sheet or not, and together also with such additional land as the Secretary of the Interior may deem necessary for monuments, markers, tablets, roads, highways, paths, approaches, and to carry out the general purposes of said sections. As title is acquired to parts of the land herein authorized to be acquired, the Secretary of the Interior may proceed with the establishment of the park upon such portions so acquired, and the remaining portions of the lands desired shall be respectively brought within said park as titles to said portions are severally acquired.