306 Field Columbian Museum — Geology, Vol. I. 



deeply hollowed and rounded so that the contours of the mass are curved, 

 and at one of the edges it extends out in the form of a thin wing. On 

 one side near the base are two especially deep and well-marked pits side 

 by side, one somewhat conical in shape, the other broadly concave. 

 The diameter of the conical pit is about 45 mm. (1^ inches) and its 

 depth 20 mm. (^ of an inch). The concave pit is about 63 mm. (2^ 

 inches) in diameter and 12 mm. (}4 of an inch) deep. These pits 

 (fully shown in Plate XLVI) probably mark areas of schreiber- 

 site which were fused out during the passage of the meteorite to the 

 earth. The surface of the meteorite is of a uniform dark brown color 

 from oxidation, but the depth to which oxidation has penetrated is 

 very slight, as the merest scratch with a file reveals the nickel-white 

 color of the interior. The meteorite is not of the " sweating" variety 

 and exhibits no tendency to further alteration. 



Fig. 4. Etched surface of Toluca (Los Reyes) meteorite, showing character of 

 Widmanstfttten figures. X £. 



Its substance is tough and malleable to a high degree. It is 

 medium hard, cutting with some difficulty with a hack-saw. It takes 

 a good polish, a polished surface being of silver-white to nickel-white 

 color. Relative to copper sulphate the meteorite is active. 



The iron has not been sliced, but a triangular area 63 mm. x 25 mm. 

 (2j4 inches x 1 inch) was made smooth and etched with nitric acid. 

 The surface etched easily and exhibited well-marked Widmanstatten 

 figures which are shown in Fig. 4. Two other smaller surfaces were 

 also etched on other portions of the meteorite. The figures of the 

 meteorite show that it is to be classed with Brezina's group 46 

 (Octahedrite with lamellae of medium width) or Meunier's group 7 

 (Arvaite). The bands of the etching figures are not of uniform 



