This complex of barge canals and natural channels-- most valuable waterway in America-- stretches 1,116 mi. from Brownsville, Texas, to St. Mark's, Florida. Is longer, carries more tonnage than Suez and Panama canals. Is a vital link in economy of Texas and has been one of main causes of rapid development of Gulf Coast area. The canal system was begun in 1854 when a short canal was built from Galveston Bay to mouth of Brazos River as aid to Texas trade; it was 50 ft. wide, 3.5 ft. deep and dug by hand-labor and mule teams. Later projects widened, lengthened canal along the coast. Most important period in growth of the waterway system was result of determined efforts by two Texas businessmen, Clarence S. E. Holland and Roy Miller. In 1905-07 these men organized the initial financial support, arranged construction and won congressional backing for canal improvements. By 1966 annual total tonnage of the waterway exceeded 78,500,000 tons. (1967)