64 Pa. Stat. § 262
It shall be the duty of the surveyor general, on application to him made, to issue his warrant or warrants, for not exceeding in quantity one hundred acres, to any one person who may apply for the same, to the deputy surveyor of any county, directing him to survey so much of the bed of any of the public navigable rivers of this commonwealth, as may be called in said application, beginning at a point designated in the application at low water mark, on the bank of said river, and pursuing the course of said river at low water mark, as far as designated; then at right angles across said river to low water mark; thence along the shore of said river, at low water mark, to a point opposite the place of beginning; and thence across said river to the place of beginning; the original of which to be filed in the office of the surveyor general, and a copy to be directed to his deputy of the proper county, whose duty it shall be to survey the same, and make return thereof as soon as possible.
64 P.S. § 262