26 



GEOLOGY. 



gathering together of gaseous matter or scattered particles in open 

 space. 



More direct evidence is found in the fragmental structure of many 

 of the stony meteorites. Among the broken elements are fragments 



Fig. 4. — A stony meteorite showing fragmental outline smoothed by fusion in passing 

 through the air, with smaller fracture surfaces due to exfoliation later in its 

 course. The Saline, Kans., meteorite. Field Columbian Museum. (Photo, by 

 Farrington.) 



of chondri (Fig. 5). As the chondri are aggregations peculiar to meteor- 

 ites, their fragmentation implies disruption and re-assemblage in the 

 parent body, or at least disruption in an earlier stage of their history. 

 Point is added to this by the occurrence of larger chondri enclosing 

 fragments of smaller ones (Fig. 6). A very singular case of breccia 

 is presented by the Mount Joy meteorite, which is an aggregate of 

 iron fragments (Fig. 7). These various evidences of fragmentation 

 imply a previous history affected by successive conditions of accre- 

 tion and fracturing. 



The presence of slickensided surfaces (Fig. 8) implies a parent 

 body subjected to varying stresses, resulting first in fracture, and 

 afterwards in the rubbing of the fissure walls upon one another. The 

 existence of veins also implies fracture attended by subsequent filling. 



