METEORITES OF NORTH AMERICA. 461 



these names. The names associated with the two masses are chiefly those of the localities 

 where they were seen or obtained, or of parties who saw the masses or aided in their removal. 



The first published mention of the meteorite seems to have been by Velasco * in 1S50. His 

 statement, as quoted by Fletcher, is as follows: 



Between the presidio of Tucson and Tubac is a mountain range called Sierra de la Madera and a pass called Puerto 

 de los Muchachos. In it are seen enormous masses of native iron, and many have rolled to the foot of the said sierra. 

 One of the masses of a moderate size was transported to Tucson and has stood for many years in the plaza (square) of 

 the said presidio. 



The next mention was by Dr. John L. Le Conte, 2 of Philadelphia, in an oral statement made 

 by him at a meeting of the American Association for the Advancement of Science, held at Albany 

 in August, 1851. Two accounts of this statement have been published. According to the first 

 and brief official account, Dr. Le Conte, "while passing through the village of Tucson in the 

 preceding February, had observed two large pieces of meteoric, iron in use by the blacksmiths of 

 the town as anvils." They were irregular in form, and although embedded in the ground to 

 make them steady for use they were about 3 feet high. Notwithstanding the offer of a high 

 price "he was unable to get any bits broken from the anvils, but was guided to a canyon between 

 two mountain ridges in the immediate vicinity from which both pieces had been taken, where 

 the masses of the meteorites were so abundant as to have given name to the canyon." 



A year later, in July, 1852, the two large masses were seen at Tucson by John Russell 

 Bartlett, 4 then the United States commissioner for the delimitation of the United States and 

 Mexican frontier. 



One, a ring-shaped mass, of which he gives a figure, was in use as an anvil in the black- 

 smith's shop. He wrote as follows : 



It was found about 20 miles distant toward Tobac, and about 8 miles from the road, where we were told are many 

 larger masses. There is another mass within the garrison grounds, of which I did not take a sketch. With much labor 

 Dr. Webb broke off a fragment of this meteorite for the purpose of analysis. 



Bartlett described the exterior as smooth and even, the interior uneven in some parts and 

 indented. 



In November, 1854, Shepard 5 gave a description of some small fragments, the largest not 

 more than a quarter of an ounce in weight, which had been sent by Lieut. John G. Parke, of the 

 United States Topographical Engineers, on his return from Sonora. Parke had just been 

 engaged in the survey for a railroad across the continent and had chipped off the fragments 

 while at Tucson in February, 1854; he was told that there were three masses, though only the 

 two larger ones were seen by him. According to information supplied by Parke they — 

 were found in a canada of the Santa Rita Mountain, about 25 or 30 miles to the south of Tucson. Two of them were 

 shown to us by the commandante, both being used as anvils. One lies within the presidio, and is of a very peculiar 

 form, being angular and somewhat like a seal ring of huge proportions. Its exterior diameter is about 3.5 feet; its 

 interior about 2 feet. It weighs nearly 1,200 pounds. The other piece is in front of the Alcalde house. It weighs 

 about 1,000 pounds and has an elongated prismatic form, serving well the purposes of an anvil. It is partially buried 

 in the soil, but has 2 feet of its length projecting above the ground. The alcalde and commandante would not con- 

 sent to our removing the masses, even if we had had the means. 



Shepard observed numerous white inclusions as large as pin heads, which he regarded as 

 chladnite (enstatite), and remarked that the silicate upon a polished surface first became notice- 

 able after etching. He further noted the absence of crystalline structure, found the tough 

 iron, resembling white cast iron in fracture, to be very resistant to acid, proved that it con- 

 tained nickel and determined the specific gravity as 6.66. 



Smith 6 investigated material obtained from Parke. He observed unusual development 

 of Widmannstatten figures due to the filling of the hollows with silicates, and drops of iron 

 chloride upon the crust. He also determined the specific gravity at 6.52 to 7.13 and from his 

 analysis (see I below) derived the following composition : 



Nickel iron 93. 81 



Chromite 0. 41 



Schreibersite 0. 84 



Olivine 5. 06 



100. 12 



