JUNE, 1910. METEORITE STUDIES III] — FARRINGTON. 167 
zina as breccia-like. This term should be understood however, in the 
same sense in which Brezina uses it, 1. e., as an imitation of brecciated 
structure, without an actual clastic origin being assumed.* The writer 
knows of no meteorite in which this structure is so strongly marked 
as in Leighton. Besides the spotting already referred to, the dark 
mass of the meteorite is also speckled by numerous chondri of various 
sizes and shapes but in general more or less circular in outline and 
ranging from 2 mm. in diameter down. The color of these closely 
resembles that of the light-colored spots just referred to. There 
is also a thick sprinkling of metallic grains. These are as a rule 
small, independent of each other and very irregular in outline. 
Some of the larger ones are elongated, one seen being 4mm. long 
and 7mm. wide. The distribution of the metallic grains as a whole 
is comparatively uniform, except that they tend to encircle the 
chondri. Troilite is to be seen in the form of grains, but is much 
less abundant than nickel-iron. At one point, however, a large 
nodule of a somewhat crescentic form occurs which has a length of 
tr millimeters and a width of 5 millimeters. This troilite is of bronze- 
yellow color, brittle, and slightly magnetic. 
The texture of the stone is firm and compact so that it breaks with 
difficulty and takes an excellent polish. The specific gravity obtained 
by weighing the whole stone was 3.604. 
Under the microscope, chondri appear to be much more numerous 
in the dark-colored than in the light-colored portions of the sections. 
This difference is doubtless in part due to the greater contrast in 
which the chondri are thrown by the dark-colored background, but 
there is also a real relative scarcity of chondri in the light-colored por- 
tions. The line of demarcation between the light and dark-colored 
portions is as sharply distinguished under the microscope as to the 
naked eye. Leighton in this respect, therefore, forms an exception 
to other brecciated chondrites, if Cohen’s statement in regard to the 
latter is accepted, for he states that the megascopically sharp-appear- 
ing boundaries of the differently colored areas of such meteorites dis- 
appear under the microscope.t Yet the difference in appearance of 
the two portions of Leighton as seen under the microscope is not 
sufficient to establish the existence of a true brecciated structure in 
the sense that it is certain that the mass was at one time broken up 
and recemented or that fragments of different origin are here seen 
cemented together. The appearance rather suggests that a dark- 
* Jahrb. K. K. Geol. Reichsanstalt, Wien, 1885, xxxv, 172. 
t Meteoritenkunde, Heft II. p. 63. 
