- 13.064 and the great shoulder of the south-pointing mountain-spur
“Mountain spur” has its own sub-entry in the OED, but no hyphen is to be found therein, even with the examples. I’m calling this one a JRRT original spelling.
“mountain, n. and adj.” OED Online, Oxford University Press, June 2017, http://www.oed.com/view/Entry/122893. Accessed 19 September 2017.