If Baja California is poor in species of organic life, Nature has compensated it in the mineral world, and that peninsula is considered one of the most highly mineralised parts of the North American continent. Copper, silver, and gold are among its most important products, and quicksilver, opal, sulphur, and rock-salt exist. The famous Boleo copper mine is situated in this territory, and some extensive _placer_ gold mines are found near Ensenada. The principal towns are La Paz, the capital of the southern district, and Ensenada, of the northern. Returning to the Mexican mainland we come to the states lying to the south of those already described. Beginning at the west, as before, we have the State of Sinaloa. This long narrow region lies between the Sierra Madre on the east and the Pacific Ocean and Gulf of California on the west, with a coast-line nearly 400 miles in length. Its area is 27,000 square miles, with a population of about 297,000 inhabitants. Topographically the state may be divided into three zones--the coast, the foothills, and the mountains; and in this it reminds the traveller of California, to which it bears resemblance in many physical and climatic respects. The coast zone consists of a well-watered and fertile strip, producing all the crops of the tropics. Next comes the foothill zone, rising gently to an elevation of 2,000 feet, and merging into a fine timbered belt alternating with extensive natural pastures. Well-watered valleys intersect this zone, capable of much cultivation, and with splendid possibilities for irrigation, cattle-raising and timber-cutting. Leaving this we enter on the more broken and mountainous country, with a heavy growth of pine and oak forest, grazing lands, and frequent streams, extending up to 4,000 or 5,000 feet elevation. This also is the rich mineral-bearing zone, whose oil deposits have justly caused the state to be considered among the foremost in the Republic in this field. The Sierra Madre has a general and continuous elevation above sea-level throughout the great length of this state, of 8,000 to 12,000 feet, except the passes, which are crossed at much lower altitudes. The mountains give rise to numerous rivers, and the state may be considered more freely endowed with water-courses than any other in the Republic. Among the first of these is the great River Fuerte, with a large volume of water: and with ten other important streams it rises amid the snow and rain of the Sierra, flowing thence through fertile valleys to the Pacific Ocean.