ELIZABETH TUNNEL, 6o m. N. of Los Angeles, Calif., is the longest of the 164 Los Angeles aqueduct tunnels, being 5.1 m. in length. It was constructed through the Coast Range moun tains, a region of great topographic difficulty, at a cost of $70.20 per ft., requiring five years to bring it to completion (Feb. 28, 1911) . Horseshoe in shape, it was constructed from two headings, 20 m. from a railroad base, is lined throughout with concrete, and measures 9 ft. 6 in. in width and 1 o ft. 1 o in. in height.