Are you sure that the cemetery you are looking for is in Webster Parish? Mt. Zion in Webster Parish is located on Hwy. 518. There are no Vanarsdales listed as being buried in this cemetery. I wonder if you may be looking for a cemetery located in Bossier Parish. Haughton is located in Bossier Parish and the Vanorsdale Cemetery containing the graves of possible descendants of William is located near Bossier Parish.
I also tried doing a search on Find A Grave but the site is apparently having problems.