alluvium in text of tables. 



The publication also includes an exellent schematic of water supply 

 and routing options within the Lake Bowdoin Refuge. 



Lake Mason. 



Bibliographic source: Geoindex lat-long search. 



Author: Zimmerman, E.A. 



Title: Preliminary report on the geology and ground water 

 resources of parts of Musselshell and Golden Valley 

 counties, Montana. 



Series: MBMG Information Circular no. 15 



Date: 1956 



Another early and minimal MBMG ground water effort. Map shows Lake 

 Mason entirely underlain by "alluvium", which includes lacustrine 

 deposits. Text describes "alluvium" of the Lake Mason basin as up 

 to 40 feet thick but high in silt content, with small well yields. 



The "alluvium" (or lacustrine silts) of the Lake Mason basin are 

 mapped as overlying the Lance formation throughout. The Lance 

 (uppermost Cretaceous) is composed of repeated sequences of 

 sandstone, shale, clay and coal. The sandstone intervals are 

 described as dependable but relatively low-yield aquifer(s). 

 Inferred structure (not shown on map) appears to be anticlinal, so 

 ground water discharge to the basin may be important. 



Extensive areas of terrace gravels underlie higher portions of the 

 basin, especially in the north. Extensive areas of Bearpaw Shale 

 around basin margins, some Judith River Formation exposed. [Some 

 proper structural mapping would be useful.] 



Ground water from the Lance formation is described as relatively 

 mineralized compared to Eagle and Kootenai aquifers. Generally, 

 Lance Formation groundwater (6 samples) is relatively sodic and 

 sulfate rich. 



Bibliographic source: Geoindex lat-long search 

 Author: Reeves, Frank 



42 



