shows the till in the Furnell area to be part of a significant end 

 moraine complex related to a glacial advance position extending 

 through but not beyond the gaps between the buttes of the 

 Sweetgrass Hills. Beyond the mapped extent of end moraine, this 

 map shows till ("ground moraine"), presumably related to older 

 glacial advances. 



Bibliographic source: Montana State Library optical disk catalog 



Author : Tuck , L . K 



Title: Reconnaissance of geology and water resources along the 

 north flank of the Sweet Grass Hills, north-central Montana 



Series: U.S. Geological Survey Water-Resource Investigations Report 

 93-4026 



Date: 1993 



Reconnaissance geologic mapping at 1:100,000 scale shows the site 

 overlying the shaley upper part of the Eagle Sandstone of Late 

 Cretaceous age. The western part of the kettle field is shown 

 underlain by Late Cretaceous Claggett Shale. Till underlying the 

 sample wetland and adjacent kettles is not shown. The text states 

 that glacial deposits typically do not exist much above 5000 feet, 

 and probably do not exceed 50 feet in thickness in foothill areas 

 (references include several on glacial geology). The Claggett 

 Shale is described as "nearly impermeable" and as having bentonite 

 beds, especially in it's lower portion. 



Generalized potentiometric surfaces are mapped for the aquifers 

 identified in the area (including the "interstratif ied sand and 

 gravel aquifer" of glacial origins), but do not extend as far south 

 as the sample site, where there do not appear to be any data. 



Three chemical analyses from groundwater in glacial deposits 

 between the sample wetland and Whitlash show calcium-bicorbanate 

 (±sulfate) water types with total dissolved solids between 300 and 

 700 mg/1. 



This publication includes what appears to be a thorough review of 

 geologic literature pertinent to the Sweet Grass Hills, including 

 some with relevance to the Oilmont Wetland site. 



Bibliographic source: U.S. Geological Survey WRI 93-4026 (see 

 Furnell WPA entry.) 



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