The Arroyos and Foothills Conservancy continues its hiking series this Saturday, Oct. 22.   Learn about the 1,200-million-year geologic history of Rubio Canyon in the Altadena foothills with docent John Wros. Tucked away at the foot of one of the fastest-rising mountain ranges in the United States, the canyon holds a number of clues to that range’s development. Meet at the base of Camp Huntington Road, where it intersects with E. Loma Alta Drive, at 9 AM. The trail is moderate — about one mile each way, with a 500-foot elevation gain.