Map of the river Sabine, from its mouth on the Gulf of Mexico in the sea to Logan's Ferry in latitude 31⁰58ʹ24ʺ north : shewing the boundary between United States and Republic of Texas, between said points as marked and laid down by survey in 1840 under the direction of the commissioners appointed for that purpose, under the 1st article of the convention signed at Washington, April 25th, 1838