The first American known to see the San Joaquin River was likely Jedediah Smith, a renowned mountain man, fur trapper and explorer. In 1826, Smith arrived in Mission San Gabriel Arcángel, California, when the region was under control of the Mexican government. As this was in violation of a law which prevented foreigners from entering California, and he could have been arrested for spying, he traveled north into the San Joaquin Valley, searching for populations of beaver. Smith noted the fertility and natural beauty of the area, and the apparent peace of the Native Americans living in the villages he passed. His expedition then turned east in an attempt to cross the Sierra Nevada. They tried to summit the range by way of both the Kings River and the American River (a tributary of the Sacramento), but it was early spring and the snow was too deep. Finally, they crossed the mountains along the Stanislaus River canyon, becoming the first recorded whites to cross the Sierra Nevada on foot. It is still disputed over whether Smith's party discovered gold on the San Joaquin or one of its tributaries. Although some of his men confirmed it, Smith did not make any mention of the precious metal in his journal.