This is a cropped closeup of a preceding photo. The sign on the left says "Cardale Grove", "All Boats Welcome" and "Admission to Tower - Telescope 25c." The sign on the side of the boat says "Biscayne Navigation Co." and "Everglade Trip."
Large high resolution prints of the entire image (not this cropped version) are available at:
http://www.shorpy.com/node/9214?size=_original