After further discussion with paleobotanist, chocolate layer may in fact be alluvial deposit natural to the plateau on which site was built. Still a possibility, however, that this natural deposit was "prepared" for construction activity by leveling its surface (see Antonia's report on soil profile on site). The walls of the opus reticulatum structure were built into this deposit. While not as labor intensive as moving large amounts of soil from elsewhere to create an artificial level surface, the investment of leveling a large area for a large construction project and the fact that the structure was built on "virgin soil" are both important insights.

Chocolate layer! Possible leveling layer found in W half of Marzuolo plateau, although debate continues, and it could also be a natural deposit. It does not appear to be an alluvial formation, however, based on pollen analysis and cereal pollen and presence of lapili, meaning soil is not sterile.