II. A. Ward — Colombian Meteorite Localities. 



Fe 92-30 



Ni -. -- 652 



Co . 0-78 



Cu 0-02 



P 0-36 



S 0-04 



C 0-18 



Cr tr. 



100-20 



If C, P, and S are calculated as cohenite, schreibersite, and troi- 

 lite, respectively, the above separate as follows : 



Cohenite. Schreibersite. Troilite. Nickel-iron. 



Fe 2-45 135 0-07 88 43 



Ni 0-06 0-62 .. . 584 



Co 0-01 0-01 ... 0-76 



Cu ... ... 0-02 



P. ... 0-36 



S ... ... 0-04 



C 0-18 



Cr ... ... tr. 



2-70 2-34 011 95-05 



The nickel-iron has the composition of kamacite, which corre- 

 sponds with the microscopic state, taenite and plessite wanting. 



Cohenite is in most cases not to be distinguished from schreiber- 

 site otherwise than by chemical proofs ; and for this reason by 

 many authors carbon is not counted as cohenite, but accredited 

 to nickel-iron. It has been shown, however, by Moissan and 

 Osmond that cohenite constitutes the outermost layer on the 

 schreibersite corona which surrounds the nuggets of troilite and 

 graphite. Where these two companions have been distinguished, 

 they proved to be developed in nearly equal quantities. For this 

 reason C is to be calculated as cohenite where cohenite and 

 schreibersite have not been distinguished. 



The iron of Santa Rosa is a member of the Zaeatecas group of 

 brecciated octahedrites. Three localities have furnished these — 

 Zacatecas in Mexico, known since 1520, Santa Rosa in Colombia, 

 found in 1810, and Barranca Blanca in Chile, found in 1855. 



Dr. Akistides Brezina. 



Vienna, June, 1906.'' 



The description bj T Cohen, referred to by Brezina,* is the 

 earliest in which Santa Rosa is distinguished as an octahedrite. 

 According to this, the octahedral structure is not uniform 

 throughout an etched face ; but the lamellae are differently 

 oriented over each of the small areas up to 2-5 cm across, into 



* That referred to on page 2 of this article. 



