ART. 21 OXIDATION OF METEORIC lEONS — SHANNON 9 



Walker," who makes it a distinct species, a nickel equivalent of 

 magnetite with the formula NiFe204 or NiO-FegOs. The mineral is 

 black, very strongly magnetic, and has a metallic luster, hardness 

 about 5 and specific gravity 5.165. 



These ferrites of nickel, copper, and cobalt are also referred to 

 by Frebold and Hesemann,^^ in their paper on the iron oxides which 

 is further referred to below. 



The natural trevorite yielded the following results upon analysis : 



Fe^Os 66. 24 



FeO 1. 96 



NiO 29. 71 



MgO . 24 



SiO^ ^--i I 1. 40 



H2O ^ .36 



99.91 



EESIDUAL MASS OF IRON OXIDES, PRESUMABLY METEORIC, FROM 

 COLDWATER, COMANCHE COUNTY, KANS."^ 



The mass, upon which the following discussion and description are 

 based, was submitted for examination to Dr. George P. Merrill by 

 Prof. H. H. Nininger, of McPherson College, Kansas. If meteoric 

 it was obviously of an old fall regarding which no historical data 

 were to be had. The severed mass, weighing 18.545 kilos, had the 

 appearance of a somewhat flattened septarian nodule, the surface of 

 which had been checked by weathering and oxidation. Tests showed 

 the presence of nickel, but a sawing of the mass through the middle 

 showed it to be composed essentially of iron oxides, compact exter- 

 nally but more porous within with no structure indicating meteoric 

 origin, although there were revealed a few specks of minute size of a 

 material of tin white color and high metallic luster. Further slicing, 

 however, revealed other surfaces traversed by platy areas of softer 

 and more porous nature than the surrounding material which were 

 arranged in lines giving triangular intersections reminiscent of the 

 medium coarse octahedral structure of meteoric irons. Since the 

 evidence seemed to suggest a meteoric origin for the mass of iron 

 oxides of which the individual was composed it was submitted for 

 analysis to Dr. J. Edward Whitfield. Doctor Whitfield's analysis 

 gave the following results: 



^o Thos. L. Walker. Trevorite a distinct mineral species. Contrib. to Canadian 

 Mineralogy. Univ. Toronto Geol. Ser. No. 16, pp. 53-54, 1923. 



1' G. Frebold and J. Hesemann. Uber magnetiscben und nicbtmagnetischen eisenglanz, 

 etc. Centralbl. Min. Abt. A. No. 10, pp. 314-321, 1926. 



" The writer is indebted to Doctor Merrill for the notes on the present material and for 

 the analysis by Doctor Whitfield. 



