The Plague Market At Merrivale

Whenever I'm crossing Dartmoor on the pretty route down to Cornwall I try to stop off at Merrivale, there's always something new to find.

No one has mentioned yet the strange little stream that runs along behind the car park area, check it out next time as you walk down toward the avenues, can it really be flowing back uphill? It certainly *looks* like it! Also why does it chose to follow the contours of the slope when any self respecting water would surely run down at right angles?

Another riddle to add to the Merrivale enigma :)

You can see the stream in question running left -> right in this ariel photo courtesy of multimap.com:

multimap.com/map/photo.cgi?client=public&x=256024&y=74832&scale=5000&width=700&height=410