Hi Emma! I don't have any knowledge about this particular cemetery, but I can give you some ideas on how to find out. First, I would recommend posting this query on the Lamar Co. Board. When you are on the Texas Genforum page, look at the upper right and you'll see "Counties for the State". Click that and it will give you a list (all 254 of them, bless our hearts!).
It's quite long, although the latest article is from 1998. But you may want to contact either Ron Brothers or Betsy Mills through the Lamar Co. US GenWeb site and they may have some more updated info. They do fantastic work.
Just some ideas. Hope they help! Good luck! Andrea