It is stated by several persons who have visited Southern Arizona, among whom Dr. Horn may especially be mentioned, that it is universally believed, and vouched for by apparently trustworthy explorers, that there are many large masses of iron near the summit of the range next east of Tucson. This is called on the latest map of Arizona, (that published by Mr. Gird) the “Sierra de la Santa Caterina.” Whether this is the same as the “Sierra de la Madera,” mentioned by Velasco, as the locality of “enormous masses of pure iron, between Tucson and Tubac,” I have been unable to ascertain. Dr. J. B. Trask saw, in August, 1849, a large mass of meteoric iron, at the village of Rio Florida, partly buried in the ground at the corner of the plaza. This may, perhaps, be the same mass mentioned by Mr. Bartlett, as existing “at the Hacienda de Concepcion, on the road from Chihuahua to Rio Florida.” Dr. Trask, however, has a distinct recollection that the mass he saw was at the village of Rio Florida, and not at the Hacienda. Dr. Veatch saw, in 1849, a large mass of iron at Santa Rosa, Coahuila, which was then in use as an anvil, at a blacksmith’s shop, and was informed that many pieces of native iron had been used there for various purposes. The mass which Dr. Veatch saw, was of about the size of an ordinary anvil. It was said to have been brought from the mountains northwest of the town. This statement corroborates that of Schott, in the Mexican Boundary Report. (Vol. I, Part 2, page 34.) It is a remarkable fact, considering the abundance of meteoric iron near our borders, that no meteorite, either stony or metallic, has yet been found within the limits of California. The piece of iron from Honcut Creek, found by Dr. Trask, and supposed to be of celestial origin, proved, on careful examination, to be ordinary cast iron. A fragment of the mass was referred to Professor Brush, and pronounced by him not to be meteoric. The existence of a piece of cast iron, in the locality where this was discovered, is not easily explained. In connection with what has just been said of the existence of meteoric iron in California, it should be added, that Dr. J. G. Cooper thinks that he observed some small pieces of native iron on the Mohave River, a little above its sink. By accident no specimen of this supposed meteorite were saved, so that it is not possible to say that Dr. Cooper may not have been mistaken. The attention of explorers in that region is invited to this supposed locality.