The most celebrated modern localities are Arivaca, (also anciently famous as Aribac,) Sopori, the Arizona mountains, the Santa Rita range, the Cerro Colorado, the entire vicinity of Tubac, the Del Ajo, or Arizona copper mine, the Gadsonia copper mine, and the Gila river copper mines. These last are situated directly upon the Gila, only twenty-five miles from its mouth. The writer assures the public that there is no room for doubt as to the authenticity of these statements, or the immense resources of the new Territory in silver, copper, and probably gold. As late as 1820, the Mina Cobre de la Plata, (silver copper mines,) near Fort Webster, north of the Gila, were worked to great advantage; and so rich was the ore that it paid for transportation on muleback more than a thousand miles to the city of Mexico. Every exploration within the past few years has confirmed the statements of the ancient records. The testimony of living Mexicans, and the tradition of the country, all tend to the same end. Col. A. B. Gray, Col. Emory, Lt. Michler, Lt. Parke, the Hon. John R. Bartlett, late of the United States Boundary Commission, all agree in the statement that the Territory has immense resources in silver and copper. Col. Emory says in his report: "On account of the Gold Mania in California I kept the search for gold and other precious metals as much out of view as possible, scarcely allowing it to be a matter of conversation, much less of actual search. Yet, enough was ascertained to convince us that the whole region was teeming with the precious metals. We everywhere saw the remains of mining operations, conducted by the Spaniards, and more recently by the Mexicans." The report enumerates at considerable length the various localities examined by Col. Emory's party, and others, of which there could be no doubt. In view of these authorities, it is hoped that those who will not believe upon any evidence, will be content in their own incredulity. The most authentic reports of these immense mineral resources have been used as authorities against their existence. The authors of these denials either have never read what they pretend to quote, or think no one else has. The Hon. T. Butler King, who was the first to reveal to an incredulous public the wonders of the California gold mines, has had the singular good fortune to be also among the first to publish correct and authentic information relating to the silver treasures of Arizona. His report upon the resources of the new Territory has all the charm to the reader that his California report had, and its brilliant predictions will be as fully realized. To Gray and Emory is the country most indebted for the earliest and most important discoveries.