This seems to refer to the memorial rotunda in the middle of the cemetery where pioneers are listed alphabetically.
Site 432 Harry Bryghmen Roberts buried 13 Feb 1897 aged 18 433 John Roberts buried 17 Feb 1914 aged 42 434 Mary Roberts buried 2 Nov 1906 435 Peter Roberts buried 4 Feb 1895 aged 48 436 William Roberts buried 12 Jun 1902 aged 43 437 William Joseph Roberts buried 3 Apr 1916 aged 44 (Although the date of burial matches William Roberts d. 1916, the inclusion of middle name of Joseph seems spurious.) 438 Agnes Hanna Robertson buried 15 Sep 1908 aged 63