...I always wonder why this thing
fascinates me every time I go to
Marquette; today I decided it looks like
a church with the light streaming in..

Some links to the history of this structure are
HERE
and an artist's rendering of a proposed renovation to
make the old ore dock function for cruise ships is
HERE
...the "flaps" at the sides of the dock are actually chutes
that let coal or ore be offloaded and there was probably
a conveyor to get the ore or coal to the railroad cars
that transported it...