Along the shores of the Pacific Ocean, from the 42° down to the 34° North, the climate is much the same; the only difference between the winter and summer being that the nights of the former season are a little chilly. The causes of this mildness in the temperature are obvious. The cold winds of the north, rendered sharper still by passing over the snows and ices of the great northern lakes, cannot force their passage across the rocky chain south of the latitude 44° N., being prevented by a belt of high mountains or by impenetrable forests. To the eastward, on the contrary, they are felt very severely; not encountering any kind of obstacles, they sweep their course to the very shores of the Gulf of Mexico, so that in 26° N. latitude, on the southern boundaries of Texas, winter is still winter; that is to say, fire is necessary in the apartments during the month of January, and flannel and cloth dresses are worn; while, on the contrary, the same month on the shores of the Pacific, up to 40°, is mild enough to allow strangers from the south, and even the Sandwich islanders, to wear their light nankeen trowsers and gingham round-abouts.
There is also a wide difference between the two coasts of the continent during summer. In Upper California and the Shoshone territory, although the heat, from the rays of the sun, is intense, the temperature is so cooled both by the mountain and sea-breeze, as never to raise the mercury to more than 95° Fahrenheit, even in St. Diego, which lies under the parallel of 32° 39'; while in the east, from 27° in South Texas, and 30° at New Orleans, up to 49° upon Lake Superior, the mercury rises to 100° every year, and frequently 105°, 107° in St Louis, in Prairie du Chien, Green Bay, St. Anthony's Falls, and the Lake Superior.
The résumé of this is simply that the climate of the western coast of America is the finest in the world, with an air so pure, that during the intense heat of summer a bullock, killed, cleansed, and cut into slices, will keep for months without any salting nor smoking.
Another cause which contributes to render these countries healthy and pleasant to live in is, that there are, properly speaking, no swamps, marshes, nor bayous, as in the United States, and in the neighbourhood of Acapulco and West Mexico. These lakes and bayous drying during summer, and exposing to the rays of the sun millions of dead fish, impregnate the atmosphere with miasma, generating typhus, yellow fever, dysenteries, and pulmonary diseases.
If the reader will look over the map I have sketched of the Shoshone country, he will perceive how well the land is watered; the lakes are all transparent and deep, the rivers run upon a rocky bottom as well as all the brooks and creeks, the waters of which are always cool and plentiful. One more observation to convince the reader of the superiority of the clime is, that, except a few ants in the forest, there are no insects whatever to be found. No mosquitoes, no prairie horse-flies, no beetles, except the ceconilla or large phosphoric fly of California, and but very few worms and caterpillars; the consequence is, that there are but two or three classes of the smaller species of carnivorous birds; the large ones, such as the common and red-headed vulture and crow, are very convenient, fulfilling the office of general scavengers in the prairies, where every year thousands of wild cattle die, either from fighting, or, when in the central deserts, from the want of water. On the western coast, the aspect of the country, in general, is gently diversified; the monotony of the prairies in the interior being broken by islands of fine timber, and now and then by mountains projecting boldly from their bases. Near the sea-shore the plains are intersected by various ridges of mountains, giving birth to thousands of small rapid streams, which carry their cool and limpid waters to the many tributaries of the sea, which are very numerous between the mouth of the Calumet and Buonaventura. Near to the coast lies a belt of lofty pines and shady odoriferous magnolias, which extends in some places to the very beach and upon the high cliffs, under which the shore is so bold that the largest man-of-war could sail without danger. I remember to have once seen, above the bay of San Francisco, the sailors of a Mexican brig sitting on the ends of their topsail yards, and picking the flowers from the branches of the trees as they glided by.
In that part of the country, which is intersected by mountains, the soil is almost everywhere mineral, while the mountains themselves contain rich mines of copper. I know of beds of gallena extending for more than a hundred miles; and, in some tracts, magnesian earths cover an immense portion of the higher ridges. Most of the sandy streams of the Shoshone territory contain a great deal of gold-dust, which the Indians collect twice a year and exchange away with the Mexicans, and also with the Arrapahoes.
The principal streams containing gold are tributaries to the Buonaventura, but there are many others emptying into small lakes of volcanic formation. The mountains in the neighbourhood of the Colorado of the West, and in the very country of the Arrapahoes, are full of silver, and perhaps no people in the world can show a greater profusion of this bright metal than these Indians.
The Shoshone territory is of modern formation, at least in comparison with the more southern countries where the Cordillieres and the Andes project to the very shores of the ocean. It is evident that the best portion of the land, west of the Buonaventura, was first redeemed from the sea by some terrible volcanic eruption. Until about two centuries ago, or perhaps less, these subterranean fires have continued to exercise their ravages, raising prairies into mountains, and sinking mountains and forests many fathoms below the surface of the earth; their sites now marked by lakes of clear and transparent water, frequently impregnated with a slight, though not unpleasant, taste of sulphur; while precious stones, such as topazes, sapphires, large blocks of amethysts, are found every day in the sand and among the pebbles on their borders.
In calm days I have often seen, at a few fathoms deep, the tops of pine trees still standing in their natural perpendicular position. In the southern streams are found emeralds of very fine water; opals also are very frequently met with.
The formation of the rocks is in general basaltic, but white, black, and green marble, red porphyry, jaspar, red and grey granite, abound east of the Buonaventura. Quartz, upon some of the mountains near the sea-shore, is found in immense blocks, and principally in that mountain range which is designated in the map as the "Montagne du Monstre," at the foot of which were dug up the remains of the huge Saurian lizard.