outcrops in the immediate area of the wetland to be composed of the 

 Mount Shields Formation and Bonner Quartzite of Proterozoic Y 

 (Belt) age. The Mount Shields Formation is dominantly argillitic 

 and quartzitic, along with other noncalcareous lithologies. The 

 Bonner Quartzite is dominantly feldspathic. 



Upgradient areas presumed to have contributed sediment to the 

 Placid Creek glacier include outcrops of the underlying Shephard 

 and Mount Shields Formations, described as having minor limestone 

 components but consisting primarily of argillite, siltite and minor 

 quartzite. The contributing area does not appear to include 

 outcrops of Helena Formation or other dominantly carbonate 

 formations. 



Bent Flat 



Bibliographic source: Geoindex lat-long search 



Author: Mudge, M.R. and R.L. Earhart 



Title: Geologic map of the Bob Marshall and Great Bear 



Wildernesses and adjacent study areas, northwestern 

 Montana. 



Series: USGS Miscellaneous Investigations Series Map 1-2181 



Date: 1991 



Regional mapping at 1:125,000 scale shows the Bent Flat area as 

 undifferentiated glacial material and the ridges within the 

 drainage as undifferentiated Cambrian (heavily carbonate lithologic 

 descriptions) and Belt (Sheppard and Mount Shields Formations). 

 Structures include a buried fault transecting Bent Flat, striking 

 north-northwest. This is the most legible map compilation for the 

 area. 



Bibliographic source: Geoindex lat-long search 



Author: Mudge, M.R. and R.L. Earhart 



Title: Bedrock geologic map of part of the Northern Disturbed 

 Belt, Lewis and Clark, Teton, Pondera, Glacier, Flathead, 

 Cascade and Powell Counties, Montana 



Series: U.S. Geological Survey Miscellaneous Investigations Series 

 Map 1-1375 



Date: 198 3 



Regional bedrock mapping at 1:125000 scale is probably from the 



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