The Girl Who Fell Out

Now it came to pass that I walked from the elevated section of Maud Heath's causeway at Kellaways towards Langley Burrell.
And as I approached Brunel's twin-arched bridge under his railway I espied a vacant sun dress upon the stonework leading to the bridge.
Of the occupant there was no sign. She appeared to have wriggled free or simply fallen out.
I checked inside to be sure. I learned only that her name was 'Primark'.
I left the dress where it was in case she was hiding in the undergrowth.
However, the possibility that the sundress had been thrown from the window of a passing train overhead could not be excluded.
All this is perfectly true.