Could we pause here and observe the caravans bound toward the sunset, we could hardly find anywhere a more interesting study.

There were the Californian emigrant, and the Mormon with his wives and their push-carts, there were the trapper and the trader, and there were the bands of natives sometimes friendly, sometimes hovering about a caravan like a pack of hungry wolves.

There is now barely an echo of this hard period, and that echo smothered by the rush of the express train as it dashes in an hour or two so heedlessly across the stretches that occupied the forgotten emigrant days or weeks.

In the search for a route for the railway much exploration was accomplished, and these expeditions, together with those in connection with the Mexican boundary survey, added greatly to the accumulating knowledge of the desolation enveloping the Colorado and its branches.
The treaty of 1848 made the Gila the southern boundary, but the Gadsden Purchase placed it farther south, as now marked.

A number of expeditions concerned in this and railway surveys traversed Arizona in the early fifties under Whipple, Sitgreaves, Emory, and others, and the country began to be scientifically known outside of the canyons and their surroundings.