The great central valley of California, about 400 miles long and 50 miles wide, lies between the Sierra Nevada Mountains and the Coast Ranges. Its farms, orchards, orange groves, and vineyards produce immense quantities of grain, and of grapes, and other fruits. Large numbers of cattle and sheep are raised. In the southern counties many tropical fruits are grown successfully. Irrigated groves of orange, lemon, and olive trees cover thousands of acres. Other important crops are English walnuts, almonds, prunes, and figs. Copper, silver, oil, quicksilver, and salt are also valuable products, while the forest-covered mountains supply excellent lumber. Such is the wealth of California's natural resources, and San Francisco is the great port and market of this rich back country. [Illustration: PICKING GRAPES] As the Sacramento River flows into San Francisco Bay from the north and the San Joaquin from the south, the two offer cheap transportation up and down their valleys, being navigable to river steamers for over 200 miles. The great bay of San Francisco is the largest landlocked harbor in the world. Here the navies of all the nations could ride at anchor side by side in safety. Though 65 miles long and from 4 to 10 miles wide, the bay is completely sheltered from dangerous winds and storms. It is connected with the Pacific Ocean by a strait called the Golden Gate, which is 2-3/4 miles long and over a mile wide. [Illustration: THE GOLDEN GATE] Such advantages have made San Francisco a great commercial and financial center. Ships from San Francisco carry the products of California westward to all the countries bordering on the Pacific, while others sail to the Atlantic seaports of America and Europe. The outgoing steamers are loaded with wheat, cotton, canned goods, oil, barley, prunes, flour, dried fruits, leather, machinery, lumber, and iron manufactures. Incoming steamers bring raw silk, coffee, tea, copra, nitrate of soda, tin ingots, sugar, rice, cigars, coal, burlap, vanilla beans, cheese, and manila hemp. [Illustration: THE SITE OF SAN FRANCISCO] Already the foreign commerce of San Francisco amounts to more than $150,000,000 annually, and with the increasing trade of Japan and China and the shortened route to the Atlantic through the Panama Canal, the future of its foreign trade cannot be estimated. [Illustration: A FLOWER MARKET] In addition to her foreign trade, San Francisco has many growing industries at home. Printing and publishing, slaughtering and meat packing, are among the most important. The canning and preserving of fruits and vegetables is a leading industry of the city. The California Fruit Canners Association employs many thousands of people during the fruit season and is the largest fruit-and-vegetable canning company in the world. It operates thirty branches throughout the state, and its products are sent to all parts of the globe.