The soundings are in feet & tenths of a foot. "Accompanying Lt. Colonel J.D. Graham's annual report (no. 200) to Chief Top. Engineer, dated September 20th 1857." Includes text (4 notes) and "Note 5" pasted on. "Map G. No. 52." Portions near left and right margins missing from MiU copy. 1 map; 80 x 125 cm This map is in the public domain. Please attribute access and use of this digitized map to the Stephen S. Clark Library, University of Michigan Library.
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