Physcia aipolia?

The parents of Corrie Jetten have buried their beloved child Corrie here. Some putty has been applied to crudely patch up a crack in the vertical beam of the cross. On the left shoulder of the crucifix, a patch of pale lichen rests.

It closely resembles Physcia aipolia... it's just that the inside of the apothecia is the same very pale light-jade green as the prothallus, instead of black. It might still be, as Dobson mentions this colour can also be white-pruinose. Also: "rarely on nutrient-enriched walls and rocks. Now returning to many areas as pollution levels drop."