The placers were largely exhausted by 1863 .
The community hung on as a shipping port for steamboats of the Colorado River and supply base until the Colorado River shifted its course westward in 1866 , leaving La Paz landlocked .
The placers were largely exhausted by 1863 , but the community hung on as a shipping port for steamboats of the Colorado River and supply base until the Colorado River shifted its course westward in 1866 , leaving La Paz landlocked .