30 



GEOLOGY. 



matic differentiation of this kind, as well as selective weathering, did 

 not take place. This, however, does not necessarily exclude volcanic 

 action, nor nonhydrous weathering, but merely the dominant phases 

 of weathering and magmatic differentiation that prevail in the earth, 

 and probably in similar bodies having atmospheres and hydrospheres. 



Fig. 8. — A slickensided surface of the Long Island meteorite, natural size. Field 

 Columbian Museum. (After Farrington.) 



The absence of water, of hydrates, and of free oxygen adds its 

 testimony against the derivation of the meteorites from the crusts of 

 bodies like the earth. 



The high velocities and the diverse directions of the meteoritic 

 flights relative to the earth forbid assigning their origin, in general, 

 to volcanic action in the moon or any of the planets. Sufficient velocity 

 might be given by a so^r explosion, but the directions would be radial 

 and not promiscuous. Explosive action within the solar system may 



