Natural Bridges
tunnels eaten through rocks by streams, etc. There are 10 of these natural curiosities, many of them of great beauty, in various parts of the United States; that of Virginia being the most celebrated. The arch of this one is 60 feet spring, depth 200 feet, crown 40 feet thick. In Walker co., Ala., is a natural bridge in which the stone is so stratified as to resemble masonry. In Trinity co., Cal., a small river runs for 3,000 feet through an arch of 80 feet span and 20 feet high. In Adams, Berkshire co., Mass., the Hudson Brook flows for 30 rods under an arch of white marble. At the village of Natural Bridge, N. Y., Indian river flows through a series of arches. NATURAL GAS