2 PBOCEEDINGS OF THE NATIONAL MUSEUM voi. 70 



evenly encrusted excepting where broken away in striking; Nos. 3 

 and 4 (pi. 3) are both well encrusted, but 4 shows a secondary crust 

 on the upper surface, not shown in the figures. 



The texture is quite uniform and plainly chondritic. The individ- 

 ual shown in Figure 1, Plate 3, was cut in halves and from the cen- 

 tral portion was selected the material for analysis and sections. 



In the thin section the stone shows a structure and composition 

 common to those of its class — a confused, often obscure tuffaceous 

 ground carrying indistinct chondritic forms of both olivine and py- 

 roxene, as a rule not sharply differentiated from the ground but 

 showing irregular and finely granulated borders due to crushing and 

 of the nature that has given rise to the supposition — by some — that 

 the apparent tuffaceous nature of chondritic stones is really cata- 

 clastic through shock or compression. 



The pyroxenes give, in most cases, extinctions parallel to the ver- 

 tical axes; occasional larger forms have extinction angles as high 

 as 12 to 15 degrees, and hence are assumed to be clinoenstatite. 

 Rarely occurs a small, irregular, colorless area without cleavage lines 

 which might readily be assumed to be an undifferentiated residual 

 glass but that it polarizes in light and dark colors and is therefore 

 considered a maskelynite. That merrillite or apatite — or both — is 

 present is indicated by a phosphoric-acid test but neither mineral 

 was recognized microscopically. No trace of oldhamite or other 

 unusual minerals could be detected. 



The stone shows a rusty black, lusterless crust and on a freshly 

 broken surface is of an ash-gray color which quickly becomes covered 

 with rusted spots. Dark chondrules ranging in sizes in one instance 

 up to five millimeters are abundant as are also small flakes of metal. 

 As a rule the chondrules break free from the matrix. I have classed 

 the stone as a spherulitic chondrite (Cc) . 



The results of chemical investigation by Earl V. Shannon are 

 given below. 



The composition of the whole stone is as follows : 



Per cent 



Metal 6.46 



Soluble silicates 52.71 



Insoluble silicates 40. 83 



Total... 100. 00 



The composition of the metal is as follows : 



Per cent 



Iron 87.61 



Nickel 12. 13 



Cobalt *--^^- • 64 



Copper . 07 



Total 100.45 



