They are situated within a circuit of some twelve or fifteen miles, and are known as Jamestown, Wood's Creek, Sonoranian Camp, Sullivan's Creek, Curtis's Creek, French Creek, Carson's Creek, and Angelo Creek. Some of these have become places of considerable business, particularly the Sonoranian Camp, which presents the appearance of a city of canvas houses. Passing the Stanislaus River in the mountains, we proceeded to Major Kingsbury's camp near the mouth of the American River, crossing in our route the Calaveras, Moquelume, Seco, and Cosumnes Rivers; all of which have rich washings near their sources, and on their bars and islands. From Major Kingsbury's camp we ascended the American River to Cullamo Hills, where the first placer was discovered by Captain Sutter's employees in the spring of 1848. From Cullamo we crossed the country to Stockton, a new town on an estero some distance above the mouth of the San Joaquin, and thence proceeded to Colonel Cazey's camp at the straits of Carquinnes; returning via San Francisco to Monterey, which place we reached on the afternoon of the 9th instant. We found the country at this season dry and parched by the sun, the heat of which became very great the moment we crossed the coast range of mountains. The thermometer ranges as high as 113° Fah. in the shade, and above 140° Fah. in the sun. A great portion of the valley of the Joaquin is so barren as scarcely to afford subsistence for our animals, and can never be of much value for agricultural purposes. There, however, is, some excellent land on the east side of that river, bordering its large tributaries. A considerable portion of the valleys of the Moquelume, Seco, Cosumnes, and American Rivers is also well adapted to agriculture; and the broad plains lying between them furnish abundant pasture for raising stock. But the amount of good arable land, as compared with the extent of country which we passed over, is small, and I am inclined to believe that the richness and extreme fertility of certain localities have led to erroneous conclusions respecting the general character of the country. Certain it is, that while there may be found sufficient arable lands to support, if well cultivated, a numerous population, here is also a very great extent of rough and mountainous country and sandy and barren plains which are of little value. The great difficulty to be encountered in agricultural pursuits in some portions of California is the want of water for irrigation; but possibly this difficulty may be overcome in part by resorting to artesian wells. If so, much of the public land which is now unsaleable may be brought into market, and the settlement of the country greatly accelerated. I would, therefore, suggest whether it may not be advisable for our government to direct some experiments to be made at the public expense in sinking wells of this character, for even if unsuccessful as a means of irrigation,