The influx of other indigenous peoples, such as the Chiricahua Apaches, including the leaders Cochise and Geronimo occupied the area until forced removal in the late 19th century.[7] More recently, the Chiricahuas have fallen into use by people smugglers and drug cartels, who position lookouts on their peaks to warn of Border Patrol activities.[10][11] The last major eruption, 27 million years ago, created the Turkey Creek Caldera and laid down 2,000 feet (610 m) of volcanic ash which fused into welded rhyolite tuff.A one to two mile wide band of sedimentary rock running southeast to northwest from south of Portal through Paradise and up to the Dos Cabezas Mountains is the source of mineralized deposits.Cave Creek Canyon on the east side is home to the American Museum of Natural History Southwest Research Station and the small towns of Portal and Paradise.