Report of National Museum, 1890.— Merrill. 



Plate CXXV. 



Figs. 1 and 2. Concretionary pebbles of siliceous sinter. (Cat. No. 

 Fig. 3. Concretionary aragonite. (Cat. No. 36097, IT. S. N. M.) 

 Fig. 4. Pegmatite. (Cat. No. 10771, U. S. N. M.) 



, U. S. N. M.) 



