The Zuni-Bandera volcanic field covers 2,460 km2 along the Jemez lineament west of the Rio Grande Rift. An older volcanic episode, mostly from vents along the Chain of Craters, took place about 3.8-3.7 million years ago (Ma); the younger episode began about 1.7 Ma and formed an extensive area of lava flows known as El Malpais. The youngest lava flow, the McCartys flow, traveled 60 km NE, fed by lava tubes up to 29 km long. The McCartys flow was recorded in native legends and was thought to have been erupted about 1,000 years ago, but radiocarbon dating indicates an age of about 3,000 years before present. The only other dated flow of Holocene age originated from Bandera Crater about 9,000-10,000 radiocarbon years ago. An earlier flow, the massive Pleistocene Fence Lake lava flow, traveled as far as 90 km W.