Paul and Bob found Para quite a good-sized city, but on very low ground.  Along the docks of the mighty river were many kinds of boats and ships, from stately ocean-liners to the tub-like barges used to float down from Bolivia great cargoes of raw rubber.  There were numerous schooners unloading vegetables and fruit, and countless dugouts paddled by natives.  Cargadores, in their bare feet, were carrying goods in and out of the various large craft, supporting the heaviest of bundles on their bare heads.  Their faces were all shades of white, brown, and black.  Among them were negroes from Jamaica, and Spaniards, Portuguese, and mulattoes from all parts of Brazil.