AFTERNOON EXCURSION, exclusively for the accommodation of the Citizens of Brooklyn and Williamsburgh.
The new and elegant steamboat ST. NICHOLAS will, on SATURDAY afternoon, August 15th, make an Excursion to the Lower Bay, affording a fine view of all the picturesque and beautiful points in our harbor--the Quarantine Ground, the Narrows, Fort Hamilton, Coney Island and Sandy Hook Lighthouse, and return to the same landing planes by 7 1/2 o'clock P.M.
The St. Nicholas will leave Williamsburgh, near the Ferry, at 3 o'clock ; Bridge street, Brooklyn, 3 1/2 ; Fulton Ferry, do, 3 3/4 ; foot of State street, South Ferry, 4 o'clock.
Fare for the Excursion, 50 cents.
--Brooklyn Daily Eagle, Wednesday, August 12, 1846 (also the 13th)
The "Quarantine Ground" appears to have been an area off Staten Island where incoming ships anchored so the immigrants could be inspected for infectious diseases. Probably was interesting to see from a distance, but also seems kind of an odd thing to sight-see. Of course, in the 1840s, visiting an insane asylum was apparently also considered a fun excursion.
This site has some scans from Harper's Weekly, 1879.