Section from Mary Hall to flags-staff Ethan Allen /

Land-surface elevation profile of a line within Fort Ethan Allen, Alexandria Co. [now Arlington], Va.
Pen-and-ink (black) and lead pencil.
At lower right in handwriting: Transferred from Office of Chf. Engr., Defenses of Washington, to Engr. Dept. Jan'y 1866.
Imperfect: Fold-lined, rubber-stamped on verso.
Drawn in 2 segments.
LC Civil War maps (2nd ed.), 541.4
Transfer; Chief Engineers Office, War Dept.
Includes 2 strait-line diagrams of measurement points along the profile.
At upper edge: 211, L., sheet 17.
Available also through the Library of Congress web site as raster image.