Leaving Sutter's Fort, Frémont and his men headed south following Smith's trail on the eastern edge of the San Joaquin Valley until he struck the Spanish Trail between Los Angeles and Santa Fe, and headed east through Tehachapi Pass and present-day Las Vegas before regaining Smith's trail north through Utah and back to South Pass. Exploring the Great Basin, Frémont verified that all the land (centered on modern-day Nevada between Reno and Salt Lake City) was endorheic, without any outlet rivers flowing towards the sea. The finding contributed greatly to a better understanding of North American geography, and disproved a longstanding legend of a 'Buenaventura River' that flowed out the Great Basin across the Sierra Nevada. After exploring Utah Lake, Frémont traveled by way of the Pueblo until he reached Bent's Fort on the Arkansas River. In August 1844, Frémont and his party finally arrived back in St. Louis, enthusiastically received by the people, ending the journey that lasted over one year. His wife Jessie and Frémont returned to Washington, where the two wrote a second report, scientific in detail, showing the Oregon Trail was not difficult to travel and that the Northwest had fertile land. Senator Buchanan ordered the printing of 10,000 copies to be used by settlers and fervor the popular movement of national expansion.