Includes notes and 2 inset maps: "Sub-sketch showing the position of Davis' Shoal, discovered by the U.S. Coast Survey in 1846" (scale 1:400,000); "Sub-sketch showing the reconnaissance of triangulation east of Penobscot Bay Maine" (scale 1:600,000).
Depths shown by gradient tints.
"(A. bis) U.S. Coast Survey A.D. Bache Superintendent" at head of title.
"No. 2" outside upper left margin.
Removed from: United States Coast Survey, Annual report of the superintendent of the Coast Survey (1859).