Pacific Railroad Surveys
The expeditions included surveyors, scientists, and artists and resulted in an immense body of data covering at least 400,000 square miles (1,000,000 km2) on the American West.
"[1] Published by the United States War Department from 1855 to 1860, the surveys contained significant material on natural history, including many illustrations of reptiles, amphibians, birds, and mammals.
As railroads gained popularity in the eastern United States during the 1830s, Americans felt an increased incentive to expand this new technology to the western frontier.
"[4] On March 3, 1853, Congress appropriated $150,000 and authorized Secretary of War Jefferson Davis “to Ascertain the Most Practical and Economical Route for a Railroad From the Mississippi River to the Pacific Ocean.” Davis ordered Brevet Captain George B. McClellan and the Corps of Topographical Engineers (TOPOGS), a division in the United States Army established to “discover, open up, and make accessible the American West,” to fulfill this obligation.
[5][6] So the route was not just ancillary to free soil policy, but could ultimately affect the balance of power between the north and south in Congress when new states were inevitably admitted into the Union out of these regional territories.
Just three years after this compromise, Jefferson Davis strongly influenced the Gadsden Purchase to facilitate his preferred southern route which was not viable over the Colorado Plateau.
The Kansas–Nebraska Act was intended to open up new lands to develop and facilitate the construction of the transcontinental railroad, however it effectively repealed the Missouri Compromise of 1820.
Second, the secession of the South from the Union during the beginnings of the American Civil War discounted southern politicians from interfering with a plan to build a northern or central route.
After finding in Fall 1860 a practical trans-Sierra route from Sacramento over Donner Pass into the Great Basin of Nevada and after finding investors to incorporate the Central Pacific Railroad in June 1861, Judah was sent in October 1861 to Washington DC to lobby for the Pacific Railway bill to aid in the construction of the first transcontinental railroad along his trans-Sierra route.
[27] Central Pacific Railroad entrepreneurs and engineers, including Charles Marsh, who made much of their prior fortunes facilitating the mining on the Mother Lode as well as the Comstock Lode, had been involved in the Henness Pass Turnpike Company and would later invest in the Dutch Flat and Donner Lake Wagon Road (DFDLWR) servicing Meadow Lake Mining District speculation in what would be popularly known as the "Dutch Flat Swindle" which politically threatened the timely completion of the railroad.
[35] On May 10, 1869, the two rail lines joined with an honorary Golden Spike at Promontory Summit, Utah, after making a combined 1,774 miles (2,855 km) of railroad track.
With limited time and expertise, their main charge was simply collection and preparation of plants and animals to be shipped back east for further study.
This approach was described by geologist William P. Blake, who accompanied Lt. Parke's expedition: The collections in this department of science were not restricted to what was new or undescribed, as I considered it quite as interesting to know that the flora of this region were the same as those common to other parts of the country, or that they were different.
Heermann, in a letter of transmittal to Lt. Parke, commented on these difficulties: "Of the reptiles, in which these countries are very rich, I had succeeded in forming quite a handsome collection, but unfortunately the cans in which they were contained became leaky, and possessing neither the means to correct this mishap, nor the alcohol to supply that wasted, they were all lost with the exception of a few specimens which I preserved in bottles.
