Residual iron oxide deposits are common in the Taseko River region of the southwestern Chilcotin where conditions are suitable for the development of these deposits, i.e. a source of iron (i.e. usually pyritic sediments and volcanics) and relatively stable depositional conditions.

The Forrest bog iron showing, 6.5 kilometres west of Mount Warner, consists of a patch of limonite, locally up to 2.5 metres thick, that overlies glacial till east of the Taseko River. The iron was probably leached from altered pyritic tuffs of the Upper Cretaceous Powell River Formation which outcrop to the east on Wilson Ridge. It was transported down slope as sulphate solutions and deposited as bog iron near the break in slope. An inferred reserve of 74,000 tonnes of ore grading 45 per cent was estimated (Geological Survey of Canada Summary Report 1920A).