I have to locate several ship wrecks on an 1910 map (a scan of an actual 1910 map on which the labels have been erased).
I tried and failed to find an other map of that period with shipwreck symbol on it to know what to use (I need something authentic looking).
I have maps from the 1860's with a symbol that looks like this : +++ (first attachment)
I have found in the 1950's the same symbol with the one I've found on today's maps (kind of a rotate triangle with a mast on it) (2nd attachment).
Was this symbols used in the early 20th century? If not, what was used? I looked on David Rumsey's map collection and didn't find anything.