200 B. Silliman— Geological and Mineralogical Notes 
districts of the Wahsatch just named, and the occurrence of 
pyromorphite is extremely doubtful. : 
Molybdie acid, however, exists pretty uniformly disseminated 
in the mines of the Wahsatch, in the form of wulfenite, 
Although it occurs in minute quantity, it is rarely absent, and 
may be regarded as a mineralogical characteristic of the districts 
of the two Cottonwoods and of the American Fork. For this 
reason a few particulars will be in place here. 
in the ochraceous ores. In the “Emma Mine,” vugs, or 
geodes, are occasionally found lined with botryoidal, apple- 
among 
crystalline at first, and as it accumulated becoming fibrous an 
amorphous, completely enclosing and capping the other species. 
Wulfenite occurs also in this mine, as likewise in the “ Flag 
staff,” the “‘ Savage,” and “Robert Emmet,” without the cala- 
mine, but never, as far as observed, without cerussite and other 
carbonates. In the “Savage,” masses of cerussite with various 
oxides are interpenetrated by the tabular crystals of wulfenite. 
wulfe 
these districts, occurring in the magnesian to : 
Tam informed, or have observed, wulfenite has not been hither- 
to found in any of the other mining districts of Utah; but 
