22 Field Columbian Museum — Geology, Vol. III. 



structure is comb-like on account of alternating filaments of taenite, 

 but for the most part it is uniform and homogeneous. The nickel- 

 iron is malleable but hard. 



An analysis of the nickel-iron made by Mr. H. W. Nichols gave 

 the following results : 



100.04 



Schreibersite forms an accessory constituent of the meteorite, 

 distinguishable from the nickel-iron by its tin-white color and 

 granular surface. At one point in the section examined it is seen 

 uninterruptedly over an area about 4 mm. square. At another 

 point it forms a part of the wall of one of the pores, separating two 

 chrysolite blebs by a space of about 1 mm. Again it fills about 

 one-fourth part of a pore, the rest of the filling being chrysolite. 

 The occurrence of the schreibersite seems to be independent of the 

 nickel-iron, no swathing kamacite surrounding it. It is brittle, 

 magnetic, and gives the test for phosphorus with ammonium molyb- 

 date. 



The chrysolite of the meteorite occurs, as previously stated, 

 filling the pores of the nickel-iron. In spite of the smoothness of 

 the walls of the pores the chrysolite adheres firmly to them so as to be 

 removed only with difficulty. The surface of the blebs is usually 

 rounded and none showed angular facets suitable for measurement. 

 The color of the chrysolite is generally dark brown to black, though 

 occasionally a typical olivine green. Often there are variations 

 of color in the same bleb. As a rule, the color is lighter toward the 

 center and grows gradually darker toward the periphery, but occa- 

 sionally there are sectors sharply separated by being darker or 

 lighter than the remainder of the bleb. Though the blebs generally 

 appear opaque when seen as a whole, fragments the size of a pin- 

 head or larger are usually transparent. Under the microscope such 

 fragments appear clear except for opaque brown or black layers 

 scattered through them. The fragments are often magnetic before 

 heating and always so after heating. The individual blebs are mono- 

 somatic as shown by the uniform directions of their cleavages and 

 lack of zonal structure. They are considerably fissured and broken, 

 but not as much so as in the Imilac chrysolite. 



