BULL. GEOL. SOC. AM. 



VOL. 11, 1899, PL. 46 



Figviie I.— Cavity u\ki. with Thomsonite of Types I and [la, and filled with Mesolite 



< (ne-third natural size 



Figure 2.— Mesolite growing on Thomsonite of Types I am> II 

 < ine-half natural size 



MINERAL LINED CAVITY AND MESOLITE 



