J. W. Shipley — Volcanic Emanations in Alaska. 117 



tiful coloring of the incrustants being largely due to the 

 salts, oxides and hydroxides of iron. Chlorides of iron 

 were recognized bnt dne to the deliquescence of the crys- 

 tals were not identified. Ferrous and ferric sulphates 

 were collected, but the compounds were not identified. 



Magnetite and amorphous Fe 2 3 were met with every- 

 where. Considerable deposits of "Venetian Red," 

 Fe 2 3 , were forming around cracks in the side of a gully 

 from which the volcanic gases were slowly seeping. 



Vivianite (Fe 3 P 2 8 . 8H 2 0). — Several acres of the 

 mud flow are covered with a hot blue mud, six inches 

 deep, resting upon the surface of volcanic ash. The blue 

 mud is saturated with water and on cool days vapors 

 could be seen rising from the surface. A brown crust of 

 oxide of iron covers the surface and a chemical examina- 

 tion of the mud showed it to be impregnated with magne- 

 tite and vivianite (Fe 3 P 2 8 . 8H 2 0). This is one of the 

 most interesting volcanic formations in the district. 



Pyrite. — Well-developed isometric crystals of FeS 2 im- 

 bedded in a gangue composed of the phosphate and sul- 

 phate of calcium together with silica were found in the 

 wall of an inactive vent. The deposit had been ex- 

 posed by the water erosion of a surface stream flowing 

 across a line of activity in the upper valley. The deposit 

 had formed about ten feet beneath the surface of the 

 ash and was the only one of pyrite observed in the valley. 



Manganese. — Na 2 C0 3 fusions indicated the presence of 

 manganese in many of the incrustants, at times in con- 

 siderable quantities. None of its compounds, however, 

 were identified. A small deposit of a brilliant, orange- 

 yellow, highly hygroscopic, incrustant was collected along 

 the cooler marge of a small orifice. It was almost en- 

 tirely water soluble and on analysis, yielded the follow- 

 ing percentages: Mn 173, Al 175, Fe 69, Ca 11, CI 15-5 

 and F 70. I should not care to venture even a guess as 

 to what this incrustant might be. 



Tar. — A most interesting organic deposit resembling 

 coal tar in odor and appearance was observed saturating 

 the ash around fumaroles on the western slope of i v Tova- 

 rupta volcano and in the immediate neighborhood of the 

 NH 4 C1 fumaroles. One fumarole in this same area was 

 emitting nitrous acid. The gases from fumaroles in this 

 area possessed a similar tarry odor and emitted much 

 H 2 S. On analysis of the impregnated ash the deposit 

 proved to be of a very complex character. A 20-gram 



Am. Jour. Sci.— Fourth Series, Vol. L, No. 296.— August, 1920. 



