Fresh-looking, sparsely vegetated lava flows mostly erupted from fissure vents are located in valleys in the northern interior highlands between the town of Estelí and the border with Honduras. McBirney and Williams (1965) considered basaltic flows in this area to be certainly of Quaternary, and possibly of Holocene age. The lava flows near Estelí were faulted and slightly tilted during formation of the Estelí structural basin. Other youthful basaltic lava flows, one of which was erupted from the Bonete de Carrao cone, are located between Estelí and Jinotega. Well-preserved cones are also located in the area west and south of Ocotal. Some of the youthful lava flows in northern Nicaragua contain granitic xenoliths and xenocrysts of quartz.