three partners: Edwin Bartlett, Henry Chauncey, and Gardiner Greene Howland. They incorporated the Pacific Mail Steamship Company on April 12, 1848 with a capital stock of $500,000. California Gold Rush The first three steamships constructed for Pacific Mail were the , of 1050 tons, the SS Oregon, of 1250 tons, and the SS Panama, of 1058 tons. The company initially believed it would be transporting agricultural goods from the West Coast, but just as operations began, gold was found in the Sierra Nevada, and business boomed almost from the start. During the California Gold Rush in 1849, the company was a key mover of goods and people and played a key role in the growth of San Francisco, California. In addition to their maritime activities Pacific Mail also ran some of the earliest steamboats on the Sacramento and San Joaquin Rivers, between San Francisco, Sacramento, and Stockton. Domingo Marcucci came from Philadelphia in the Pacific Mail steamship SS Oregon with a knocked-down steamboat in its hold. He started a shipyard in San Francisco on September 18, 1849, on the beach at Happy Valley, at the foot of Folsom Street, east of Beale Street. Marcucci's company assembled the Captain Sutter in six weeks. Built for the Aspinwall Steam Transportation Line, owned by George W. Aspinwall, brother of William Henry Aspinwall, it was one of the first steamboats that ran between San Francisco and Stockton, in 1849. Also for the Pacific Mail, Marcucci next converted the 153 ton side-wheel steamboat El Dorado that had been rigged as a 3 masted schooner for the trip around Cape Horn, to be used for the Sacramento run. Subsequently in March 1850, for the same company, he assembled the Georgiana, a small 30 ton side-wheel steamboat made in Philadelphia, knocked down and sent by sea also for the Sacramento run. That April Georgiana pioneered the shortcut route between Sacramento and Stockton through a slough in the Sacramento–San Joaquin River Delta that was between the Sacramento River and Mokelumne River, which afterward became known as Georgiana Slough. 1850–1869 In 1850, the Pacific Mail Steamship Company established a steamship line competing with the U.S. Mail Steamship Company between New York City and Chagres. George Law placed an opposition line of steamers (SS Antelope, SS Columbus, SS Isthumus, SS Republic) in the Pacific, running from Panama to San Francisco. In April 1851, the rivalry was ended when the U.S.