Sector A of Marcigliana is almost uncoloured: La Barbaccia, Fonte di Papa and Tenuta di S. Colomba lie between two wide Tiber bends and a diagonal road.
Source: Old map, public domain
Deep river meanders cut the left half of the sheet, and ridges hatched in green fill the lower right above Le Grotte. The communes of Riano, Monterotondo and Mentana are named along the margins, and the lower edge continues into Sector B.