350 Mallet — Stony Meteorite from. Coon Butte, Arizona. 



petrographic study of meteorites, very kindly undertook to 

 have thin sections made of some fragments I sent him, to 

 examine these under the microscope, aud to secure photo-micro- 

 graphs of some of them. The notes with which he has 

 favored me are as follows, and in figs. 2, 3 and 4 the accom- 

 panying photo-micrographs are reproduced. 



Section showing structure. The black areas are nickel-iron and. metallic 

 sulphides ; the light areas are olivine and enstatite. 



"Aside from its metallic constituents, the stone consists 

 mainly of enstatite and olivine. The enstatite, which is 

 largely in excess, occurs in granular forms, without distinct 

 crystal outlines and also in chondrules of the usual fan-shaped 

 radiating and granular structures (figs. 2 and 4). In the 

 larger forms of the single crystals a condition of molecular 

 strain is manifested by the manner in which, between crossed 

 nicols, the dark wave sweeps over the surface. Such a condi- 

 tion, it may be stated, is not uncommon in stony meteorites, 

 through its full significance seems not to have been realized. 



The olivine likewise occurs in granular form and in that of 

 chondrules with the characteristic barred or grate-like and, 



