Title: Geology of the Cat Creek and Devils Basin oil fields and 

 adjacent areas in Montana 



Series: USGS Bulletin 786-B 



Date: 1927 



This is a detailed (for it's time) report on the structure and 

 stratigraphy of this area but includes no hydrology or 

 hydrogeology. Lake Mason is at the southwestward extremity of the 

 map area (map scale of 1:125,000), shown within an extensive area 

 of undifferentiated surficial deposits. Upgradient areas of South 

 Willow Creek shown with extensive areas of terrace gravels elevated 

 above drainages. Lance Formation (transitionally overlying Bearpaw 

 Shale) the principal bedrock outcrop shown in the basin. 



Structural contours on the Third Cat Creek Sand of the Kootenai 

 Formation show Lake Mason near the axis of syncline plunging 

 slightly southward(??) 



Lake Thibadeau Northeast 



Bibliographic source: None, default reference 

 Author: Ross, Andrews and Witkind 

 Title: Geologic map of Montana 

 Series: None(?) 

 Date: 1955 



Regional compilation at 1:500,000 scale shows the entire 

 contributing basin underlain by the Bearpaw Shale of Late 

 Cretaceous age. This map provides no useful information regarding 

 surficial deposits. The site is within the limits of Pleistocene 

 glaciation and is presumably underlain by till (presumably 

 calcareous) of unknown thickness. 



Neither automated searching of the Geoindex database nor manual 

 searching of the MBMG publications index revealed any more useful 

 geologic mapping of this area. 



Lakeside. 



43 



