The Patuxent River encompasses all the waters of the Patuxent River and its tributaries westerly of a line beginning at a point, at or near Lat. 38° 19.15’ N., Long. 76° 25.27’ W., then running 120° (True) to a point, at or near Lat. 38° 18.57’ N., Long. 76° 23.97’ W.