Curious, there's no issue on my side when calling up the page; here's a pretty similar picture:
https://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Sc...Does this one work? She's talking about the top of the lower part. See also:
http://www.britainexpress.com/church-history.htm?term=PulpitSo the top part of the pulpit if I'm not mistaken.
"This term doesn't appear in the text you have given in this precise form. "
To be fair, that doesn't matter because of German compound rules. Schiffahrt = die Fahrt des Schiffes/auf dem Schiff / diese Überfangung der Brüstung = diese Brüstungsüberfangung. The bigger issue I see is that the noun is much more commonly known as "Überfang" without "-ung".
Cf
"mit einem Überfang versehen"
http://www.duden.de/rechtschreibung/ueberfangenNo -ung.
Best wishes