Stratigraphic Layer Number

As you excavate downward you encounter layers one after another, and layerNumber records their order — typically 1 for the topmost recorded layer, 2 for the next, and so on. The number must be unique within a single excavation unit, so no two layers in the same unit can share it, though different units number their layers independently. This ordering is what lets Relic reconstruct the stratigraphic sequence of a unit and correlate finds with the layers they came from.