44-2 W. M. Foote — Shower of Meteoric Stones, Arizona. 



and thinner than the older crust. Moreover, the fractures it 

 covers arc hackly and irregular, and it even fails to hide occa- 

 sional protruding chondrules, indicating that the superficial 



dissipation by combustion had not proceeded far enough to 

 round off the sharper corners and smaller prominences. 



What may be termed a tertiary crust was begun subsequently 

 to the second explosion when nearing the ground at reduced 

 velocity. The genesis of this is most interestingly shown in 

 various stages. A slight discoloration, especially a tarnishing 

 of the metallic minerals, is sometimes seen. A mottled smoking 

 of the surface and an incomplete incrustation of small patches 

 is quite common and grades into a thin filmy crust (see fig. 5). 



Fig. 5. 



Fru. 5. Primary crust at left. Tertiary crust beginning as a smoky alter- 

 ation, x 0'85 diameters. 



On many of the smaller stones this tertiary crust is fully devel- 

 oped at the edges of the primary crust, being in fact a labiate 

 overflow of the latter. The newly fractured area often shows 

 the various degrees of fusion as its center is approached, where 

 in some cases only a smoky alteration may be seen. Rarely 

 the primary, secondary, and tertiary incrustations are exhib- 

 ited in the same fragment. 



Several dozen individuals showed the characteristic radial 

 flowage lines of viscous stone from the front, or brustseite, to 

 the back. This flow is due to the backward rush of air over 

 the molten surface. It was noted in some pieces of not over 



