El Negrillar is a group of cinder cones and compound andesitic lava flows in what was interpreted to be a Holocene volcanic field W of the Cordón de Púlar (Moreno 1985, pers. comm.; de Silva and Francis, 1991). Gardeweg (1993, pers. comm.), however, did not consider it to be of Holocene age. This volcanic field, also known as Negros de Aras, lies ~20 km N of Socompa volcano. The major Holocene debris avalanche from Socompa overlies some youthful-looking lava flows at the W margin of the complex.