Several routes had been opened across the Sierra Nevada mountains into California, but those through the Carson and Donner passes were most used. Several high ranges of mountains lay between the Willamette Valley of Oregon and the Great Valley of California, so that in the early days there was very little travel between these two territories. The overland trip required so long a time, and involved such dangers and hardships, that many preferred the water route, in spite of the fact that its ships were crowded, and the voyagers must cross the fever-infected Isthmus.
It is very interesting to note how widely different the rivers are upon the opposite sides of the Rocky Mountains. Those upon the east, with the exception of the Missouri at the Great Falls, are not marked by waterfalls after leaving the mountains. There are few cañons of importance. The streams generally flow in channels only slightly sunken below the general level of the Great Plains. The streams upon the west, on the contrary, are broken by rapids and waterfalls, and are generally buried in cañons so deep and precipitous that in places a man might die of thirst in sight of water.
No other great migration of people over the surface of the earth ever encountered such difficulties as that which pressed westward after the discovery of gold. It was at first thought that railroads could not be constructed through the mountains and deserts, and until the mineral wealth of the West became known, many men believed that the greater portion of the country was not worth taking.
It would be interesting to consider each of the main lines of railroad which connect the Mississippi Valley with the Pacific, and study the features of the country through which it runs, determining as far as possible the surveyor's reasons for selecting that particular course. Some of the railroads follow for long distances the routes of the emigrants. The emigrants, in their turn, often made use of the ancient Indian trails.
FIG. 95.—THE CARSON PASS, SUMMIT OF SIERRA NEVADA MOUNTAINS
One of the main emigrant routes to the Pacific Coast
While Nature seems to have striven to raise impassable barriers to shut off the Pacific slope from the rest of the continent, yet she failed at some points, and through the unguarded passes the wild animals and Indians first found their way. Then came the trappers, prospectors, farmers, and at last the railroad, until the wilderness was over-run.
Because of its temperate climate, abundant rainfall, and rich soil, the Mississippi Valley was rapidly settled after the pioneers had once reached it. The plains rising slowly westward toward the base of the Rocky Mountains were found to be more arid the farther they were explored. Consequently there exists a broad strip of plain which is even to-day sparsely settled. The emigrants went on to the fertile valleys nearer the Pacific, where the rainfall is more abundant. The American settlers did not then understand irrigation, although it was practised by the Mexicans to the south. Because the discovery of precious metals was first made in California, the pioneers crossed the intervening mountains without giving a thought to the mineral riches which might be concealed in their depths. Later, mines were opened in the mountains all through the arid regions. The necessity of providing food for the miners brought about the discovery that the desert lands were very productive wherever the waters of the streams could be brought to them.