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cave has been exposed by vertical erosion to easy examination. 

 These sheets vary in color, black, brown and gray predominating, 

 with an occasional stratum of bright brick red. The flows also 

 vary considerably in texture and in extent of disintegration. 



The interior of the cave is shown in Fig. 3. The floor is 

 deeply covered with a very fine-grained brown powder or dust. 

 Here and there is a block of lava that has evidently dropped 

 from the ceiling. The powder is very light in weight, and some- 



