Plate VIII.— BRECCIATED KONA DOLOMITE. 



Fig. 1. Brecciated chert in Kona dolomite from sec. 18, T. 47 N., R. 25 W. (Atlas Sheet XXXVII). The 

 gray chert is broken into fragments by Uyuamic action. The fragments are angular. They 

 arc cemented by chert and iimouite. After being thus cemented the lock was again broken 

 by later movement. The rock was again cemented by minute veins of chert and hematite. 

 Natural size. 



Fig. 2. Brecciated chert in Kona dolomite from sec. 1, T. 47 N., R. 25 W. (Atlas Sheet XXXIX). The 

 figure 18 from a chert layer between the Mesnard quartzite and tlie dolomite. The rock 

 was brecciated by dynamic action. The fragments were rubbed against one another, so that 

 many of them are partly rounded. They were then cemented by chert and hematite. Sub- 

 sequent movement again slightly shattered the rock, and the cracks thus formed were 

 healed by secondary silica. The minute veins thus j>ro(luced may be seen running through 

 both matrix and fragments. Natural size. 

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