Columbia subject headings:
Monitor (Ironclad)
Ocean bottom--Pictorial works.
Ocean engineering--United States--Interactive media.
Oceanography--United States--Interactive media.
Submarine topography--United States.
Underwater exploration--United States--Interactive media.
Harvard subject headings:
Monitor (Ironclad)
Ocean bottom--Pictorial works.
Ocean engineering--United States--Interactive media.
Oceanography--United States--Interactive media.
Submarine topography--United States.
Underwater exploration--United States--Interactive media.
Princeton subject headings: