When cavers found a pile of bones and some strange wall-markings inside 
a newly-discovered cave chamber, DigVentures was called out to 
investigate. [Yorkshire]  ... Almost immediately, we came across the 
bones, which were set in the thick, sticky cave mud, but I was instantly 
distracted by what was next to them on the wall; a set of peculiar 
linear markings in the thin layer of sediment that covered the walls. 
Looking more closely, I could see another decorative pattern on the wall 
of the cave, a patination that reminded me of the cup and ring marks 
that are a feature of prehistoric art in Atlantic Europe. Looking more 
closely, I could see another decorative pattern on the wall of the cave, 
a patination that reminded me of the cup and ring marks that are a 
feature of prehistoric art in Atlantic Europe .

See more at: 
http://digventures.com/2015/11/to-the-rescue-strange-skulls-and-weird-wall-markings/#sthash.4w7SnzC4.dpuf