If, as proposed, the Northern boundary of the Arizona Territory should enclose the Northern branches of the Gila, an agricultural region will be opened to settlement sufficient in itself to sustain the population of an immense agricultural State. Col. Bonneville, who is now at the head of a large force exploring this region, writes to the Secretary of War that it is the finest country he has ever seen, "valleys capable of sustaining a population of twenty thousand each, teeming at every step with evidences of an immense population long ago-and an ancient and superior civilization." The Hon. John R. Bartlett says of the "Salinas," one of the Northern branches of the Gila, that it alone will supply food for a great State. It must be recollected, in this connection, that the great mineral wealth of Arizona will call for and amply repay for the redemption and expensive cultivation of all the available lands, and that irrigation produces immensely greater crops than the other method of planting. Throughout the whole of Utah, irrigation has been resorted to with the greatest success. The soil in Utah, in no place that the writer saw it, could in any way be compared to that of the bottom lands of Arizona. Captain Whipple in his valuable report of exploration for the Pacific Railroad, published by order of Congress, crossed the upper part of the region alluded to, and which is watered by the Rio Verde and Salinas. He fully sustains me in my remarks on those rich valleys. "We are in the pleasantest region we have seen since leaving the Choctaw country. Here are clear rivulets, with fertile valleys and forest trees. The wide belt of country that borders the Black Forest, and probably extends along the Rio Verde to the Salinas and Gila, bears every indication of being able to support a large agricultural and pastoral population. The valley of the Rio Verde is magnificently wooded with furs and oaks, affording excellent timber. Ancient ruins are said by trappers to be scattered over its whole length to the confluence with the Salinas. We, therefore, seem to have skirted the boundary of a country once populous, and worthy of becoming so again. Besides the advantages already enumerated, the mountains in this vicinity bear indications of mineral wealth. Vol. 3, p. 93."