The Lower Viejo dacite dome is overlain by the puerta dacite dome and has a 0.1 km thick lobe-like lava. The dome has light gray lava with mottled structure due to the abundance of enclaves which are dark gray aphanitic that come in different shapes. The puerta dacite is well exposed compared to the other two domes.
The Lower Viejo dacite dome is positioned above the Puerta dacite dome and has a 0.1 km thick lobed lava flow. The dome features light gray lava with mottled structure caused by numerous enclaves, which are dark gray aphanitic in appearance and vary in shape. The Puerta dacite is more exposed compared to the other two domes.