Lower California contains valuable mines of gold, silver, copper, and lead; but, for the want of capital, very few of these are worked, and this in the rudest manner possible. Nevertheless, the labor expended on them is well rewarded; and there can be no doubt that with capital and suitable means they would yield very handsome profits. The salt mines on Carmen island are capable of supplying the whole coast of Mexico and California; already the duties on this article amount to a considerable sum. The commerce of the peninsula is now very limited, being principally confined to a coasting trade with the ports of Mexico. The whole population of the country is but little more than ten thousand, and the annual imports and exports are estimated at $300,000. But in our hands this commerce, freed from the absurd restrictions imposed by Mexico, will soon receive a very great extension. La Paz will become the principal depot of American goods for the western coast of Mexico; and in a few years most foreign goods intended for this coast will also be deposited in the warehouses of Lower California, to be transferred to the ports of Mexico at such times and in such quantities as the demands of the market may require. In the present variable state of Mexican trade, resulting from an irregular and fluctuating tariff, which differs for each port and changes with every change of general or state administration, it is frequently necessary to transfer vessels with their cargoes from one port to another, or to keep them for weeks at sea, standing off and on, so as to enable the agents to arrange the rate of duties at the custom-house before landing the cargoes. Sometimes the consignees are obliged to send their vessels to the Sandwich islands or Valparaiso until a change of administration will enable them to avoid the exorbitant demands of some petty governor or collector of customs. Moreover, the principal commercial ports of this coast (Mazatlan and San Blas) are inaccessible to merchant vessels for four months of each year, and during that time are visited only by small coasters. But, with Lower California in our possession, merchant vessels of whatever character, at all seasons and in all winds, can find a refuge in La Paz, and their cargoes despatched in such quantities and to such points of the opposite coast as circumstances may justify. This place in a few years will be what Mazatlan now is, and Mazatlan experience the fate of San Blas and Acapulco.