In 1857, President James Buchanan appointed Beale to survey and build a wagon road from Fort Defiance, Arizona to the Colorado River, on the border between Arizona and California. The survey also incorporated an experiment for the Army using camels, first proposed by Secretary of War Jefferson Davis four years earlier. Beale used camels from the Camel Corps imported from Tunis as pack animals during this expedition and on another in 1858 through 1859 to extend the road from Fort Smith, Arkansas to the Colorado River. His lead camel driver was Hi Jolly (Hadji Ali) a Greek-Syrian convert to Islam. The camels were capable of traveling for days without water, carried much heavier loads than mules, and could thrive on forage that mules wouldn't touch. But the camels scared horses and mules, and the Army declined to continue the experiment with camels. Nevertheless, the wagon road Beale built became a popular immigrant trail during the 1860s and 1870s, and it was this survey which marked out for the first time a practicable highway along the 35th parallel that has been used from that day to this. The general route of the Beale Wagon Road was followed by U.S. Route 66, the Sante Fe Railway, and Interstate 40.