The Belize River, rising in the Montaña de Dolores near Peten and crossing the British colony, is the principal highway for the commerce of Peten, the pitpans bringing down huge mahogany bowls, paddles, baskets, and other Indian goods. The Sarstun forms the southern boundary of the British possessions, and is navigable for small canoes as far as the rapids of Gracias á Dios. None but timber-cutters disturb its solitudes. The Polochic is at present the most useful river of Guatemala. It rises near Tactic, and is a foaming torrent for much of its course in Alta Verapaz. At Pansos the waters are navigable for light-draft steamers, except in very dry seasons; and not far below, its volume is materially increased by the Cahabon. It flows through the Lake of Izabal, and, as the Rio Dulce, empties into the Gulf of Amatique over a bar of sand. The Motagua is nearly parallel to the Polochic, and rises near Santa Cruz del Quiché. From Gualan it is navigable in canoes. Smaller streams are the Ulúa, Aguan, and Segovia in Spanish Honduras, which are navigable for pitpans. Finally we have the San Juan, known as one of the elements of the “Nicaragua Canal” route, but not at present navigable for boats of any size. All the rivers of Central America that can be used for commerce require a special river service; for wherever the depth of water is sufficient, the always-present bar cuts off access to vessels drawing more than six feet. Should the development of the country warrant it, the bar of the Rio Dulce could be deepened sufficiently to admit vessels drawing ten or fifteen feet.