144 ECONOMIC GEOLOGY OF SILVEETON QUADRANGLE. L bull. 182. 
Bog iron ore occurs in the swampy ground along Mineral Creek and 
in Ironton Park as a deposit from iron-bearing springs. It was for- 
merly used to some extent in Silverton as a flux for smelting, but 
lias at present no market. 
Limestone suitable for making lime occurs at several points in the 
peripheral portions of the quadrangle, and has been burned for lime 
just below Silverton to supply local demand. 
Building stone is not in much request. Good stone might undoubt- 
edly be quarried from the monzonite of Sultan Mountain were there 
any demand for a building material involving so much labor in its 
production. 
