 More restricted in exposure is the Las Negras unit, which forms basalt-andesite lava flows with prominent levees on the northwestern flank of Paniri (one of these is dated to 402,000 ± 46,000 years ago).This is considered to be the "main edifice" stage of volcano growth at Paniri.The last three units of Paniri are the Viscachas, Laguna and Llareta units.