1890. | HOWELL—DESCRIPTION OF NEW METEORITES. 97 
The inclusions are mostly irregularly arranged particles of magnetite, and negative 
crystals (prisms and minute pinacoids), also gas cavities. Sometimes the inclusions are 
parallel and sometimes perpendicular to the striation, or again slightly oblique to it. 
Enstatite. 
One grain was observed by Dr. Lane which he thought might be enstatite, although 
it could be olivine. It is yellowish, dusty with inclusions, and the extinction parallel to 
the cleavage planes and inclosures. 
Olivine. 
This mineral is recognized by its white color, high refractive power, strong double 
refraction, and irregularly developed cleavage planes. It is quite abundant and is without 
crystalline form. Its cleavage cracks are often lined with yellowish oxides or iron. The 
inclusions appear to be magnetite. 
Magnetite. 
This occurs in irregular grains and is quite abundant. It also occurs as inclusions in 
the pyroxene and olivine as well as occasionally in the feldspar. It is easily distinguished 
by its dead black color in reflected light. 
Pyrrhotite (Troilite). 
This mineral is common in some sections and rare in others. It is distinguished by 
its brownish yellow color, which is darker than that of pyrite. 
Iron. 
This mineral is wanting in some sections, but it is abundant in others, making a 
fourth to a third of their mass. It is in irregular patches,that are sometimes I to 2 m. m. 
long. It is recognized by its shining iron-grey color in reflected light. 
Alteration Products. 
All the minerals are more or less stained by a brownish to yellowish iron oxide ; 
while the white inclusions in the feldspar may perhaps be an epidotic alteration of it. 
Dona Inez Meteorite. 
The hand specimen is a crystalline mass of brown color showing grains of olivine, 
iron, pyrrhotite, etc., inclosed in the groundmass. 
This has weathered to a greater extent than the Llano del Inca, possibly due to its 
containing more iron. 
Macroscopically its composition is the same as that of the Llano del Inca meteorite, 
but the structure is considerably different, the Llano form having its feldspar lying in a 
crystalline groundmass of the other ingredients, while in the Dona form the pyroxene and 
some of the feldspar are the porphyritic ingredients in a groundmass of finer and more 
rounded granules than that of the Llano form. Further the Dona form has been more 
altered than the other. The pyroxene constituent also differs considerably as determined 
below. It would from this be doubtful if the two specimens came from the same fall, 
although as great a variation might exist in two different parts of the same mass. The 
intergrowth of the pyroxene minerals gives a structure similar to some structures observed 
in the chondritic meteorites, and is apparently due to the same cause——crystallization. Both 
these meteorites are distinctly crystalline masses, and can in no sense be considered frag- 
mental. In the Dona form besides the oxide of iron there are other alteration products 
resembling carbonates, delessite, hisingerite, feldspar, silica, etc. 
7a. Proc. Rocu. AcaD. oF Sct., Sept., 1890. 
