MINERALOGICAL CHANGES OBSERVED IN CORES OF FUNAFUTI BORINGS. 417 



Fig. 54. — Coral-substance aragonite ; cavities con- 

 taining fine calcareous detritus in process of 

 conversion into secondary aragonite. 



Fig. 55. — Coral-substance aragonite ; cavities 

 completely filled with secondary aragonite. 



Fig. 56. — Coral-substance aragonite ; cavities 

 containing secondary calcite deposited upon 

 secondary aragonite. 



Fig. 57.— Coral substance passing from aragonite 

 to secondary calcite ; cavities filled with secon- 

 dary calcite. 



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Fig. 58. — Coral substance and contents of cavities, Fig. 59. — Coral-substance aragonite, in process of 



both secondary calcite. removal by solution ; cavities filled with finely- 



divided calcareous detritus. 

 3 H 



