The baptistery, only partially preserved, is rectangular in shape (10 m x 4 m) with an apse on its western side. The walls are made of sandstone blocks, while the floor is made of basalt slabs.
The baptismal font has a hexagonal shape and is constructed with reutilised material, mostly basalt slabs. On the western side, there are three steps that allowed the catechumen to descend into the basin. Next to it is a seat built in stone and plaster, for the minister of the sacrament (bishop or priest). It is situated between two Doric capitals reversed and used as column bases that had to support, along with two others, a square canopy. The structure of African derivation generally dates from the 5^th-6^th century AD.
On a knoll small hill overlooking the area, a small ecclesiastical building, only partly preserved, was discovered to the north of the baptistery. It has a single nave or three naves structure and an apse oriented to the west. It is made of sandstone blocks, while the floor is wrought with lime. In the presbytery part of the altar table is preserved and consists of reutilised elements. During the excavations a cross, now lost, was identified on the back wall. The building has been interpreted as the ecclesia Sancti Marci (Church of St. Mark) news of which derives from medieval sources.