Section 25. The department shall have general supervision of so much of the province lands at Provincetown as lies north and west of a line beginning at a point at or near the shore of Provincetown harbor, in latitude north forty-two degrees, two minutes, and longitude west seventy degrees, eleven minutes, forty-five seconds; thence northwesterly to a point in latitude north forty-two degrees, three minutes, eight seconds, and longitude west seventy degrees, twelve minutes, forty-eight seconds; thence northeasterly to a point in latitude north forty-two degrees, three minutes, twenty-eight seconds, and longitude west seventy degrees, eleven minutes, thirty-three seconds; thence due north to a point in latitude north forty-two degrees, three minutes, forty-eight seconds; thence due east to a point in the eastern boundary of the province lands.