Hiya Austin,
I'm taking a guess here .. there are several locations today in North Belfast starting with Graymount.
They link up with each other so I'd say Graymount was a large estate near Gray's Lane and the Shore Road.
You need some assistance from the guys with the street directories ...
1907.. 1910 .. 1918 .. 1919 MaryLennon, 1909 Cos and 1911 Anthony
All the Best, Chris