THE STRUCTURE OF METEORITES 



57 



crystalline, cryptocrystalline and vitreous or amorphous struc- 

 tures may be noted. Among the polygenic meteorites, brecciated, 

 agglomerated, psammitic or sandstone-like and tuffaceous struc- 

 tures may be noted. Stratified, foliated, and fibrous structures 

 are entirely lacking. Both among monogenic and polygenic 

 meteorites occurs a kind of structure resulting from the mass 



Fig. j. — Widmanstatten figures. Meteorite from Toluco, Mexico. 



being made up largely of little spheres called chondri. The 

 structure of such meteorites is not strictly comparable to that 

 found in any terrestrial rocks. Meunier describes it by the 

 term oolitic, but the analogy is not a very close one. The 

 structure, therefore, requires a distinctive term, chondritic, 

 meaning a rock made up wholly or largely of chondri. 



CRYSTALLINE STRUCTURE. 



Iron meteorites. — Sections of most iron meteorites when 

 heated or etched by acids or other etching agent display upon 

 their surface well-marked figures formed of series of parallel 

 bands intersecting in two or more directions. These figures 



