Stratigraphy

Start Depth
End Depth
Stratigraphic Unit
Start Depth: 0.00 ft
End Depth: 98.00 ft
Unit: Pre-Illinoian 
System
Quaternary 
Series
Pleistocene Series 
Group
Pre-Illinoian 
Formation
 
Member
 
Submember
 
Start Depth
0.00 ft
End Depth
98.00 ft
Contact Accuracy
Contacts Poorly Defined Or Complete Gap 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Till - Oxidized And Unleached 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 98.00 ft
End Depth: 112.00 ft
Unit: Pre-Illinoian 
System
Quaternary 
Series
Pleistocene Series 
Group
Pre-Illinoian 
Formation
 
Member
 
Submember
 
Start Depth
98.00 ft
End Depth
112.00 ft
Contact Accuracy
Top & Base Accurate For Sample 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Till - Oxidized And Unleached 
Percent
50 
Secondary Lithology
Till - Unoxidized And Unleached 
Percent
50 
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 112.00 ft
End Depth: 135.00 ft
Unit: Pre-Illinoian 
System
Quaternary 
Series
Pleistocene Series 
Group
Pre-Illinoian 
Formation
 
Member
 
Submember
 
Start Depth
112.00 ft
End Depth
135.00 ft
Contact Accuracy
Top & Base Accurate For Sample 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Till - Unoxidized And Unleached 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 135.00 ft
End Depth: 148.00 ft
Unit: Pre-Illinoian 
System
Quaternary 
Series
Pleistocene Series 
Group
Pre-Illinoian 
Formation
 
Member
 
Submember
 
Start Depth
135.00 ft
End Depth
148.00 ft
Contact Accuracy
Contacts Poorly Defined Or Complete Gap 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Till - Oxidized And Unleached 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 148.00 ft
End Depth: 230.00 ft
Unit: Pre-Illinoian 
System
Quaternary 
Series
Pleistocene Series 
Group
Pre-Illinoian 
Formation
 
Member
 
Submember
 
Start Depth
148.00 ft
End Depth
230.00 ft
Contact Accuracy
Top & Base Accurate For Sample 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Till - Unoxidized And Unleached 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 230.00 ft
End Depth: 246.00 ft
Unit: Unknown 
System
Unknown 
Series
 
Group
 
Formation
 
Member
 
Submember
 
Start Depth
230.00 ft
End Depth
246.00 ft
Contact Accuracy
Contacts Poorly Defined Or Complete Gap 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Silt 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 246.00 ft
End Depth: 279.00 ft
Unit: Unknown 
System
Unknown 
Series
 
Group
 
Formation
 
Member
 
Submember
 
Start Depth
246.00 ft
End Depth
279.00 ft
Contact Accuracy
Top & Base Accurate For Sample 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Sand 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 279.00 ft
End Depth: 315.00 ft
Unit: Unknown 
System
Unknown 
Series
 
Group
 
Formation
 
Member
 
Submember
 
Start Depth
279.00 ft
End Depth
315.00 ft
Contact Accuracy
Top & Base Accurate For Sample 
Penetration
Complete Penetration, Gaps, Top & Base Defined 
Primary Lithology
Sand And Gravel 
Percent
100 
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments
Start Depth: 315.00 ft
End Depth: 482.00 ft
Unit: Fort Benton ("Lower Colorado ") 
System
Cretaceous 
Series
 
Group
Fort Benton ("Lower Colorado ") 
Formation
 
Member
 
Submember
 
Start Depth
315.00 ft
End Depth
482.00 ft
Contact Accuracy
Contacts Poorly Defined Or Complete Gap 
Penetration
Complete Penetration, No Gaps 
Primary Lithology
Shale 
Percent
100 
Secondary Lithology
 
Percent
Tertiary Lithology
 
Percent
Comments
Start Depth: 482.00 ft
End Depth: 614.00 ft
Unit: Dakota 
System
Cretaceous 
Series
 
Group
Fort Benton ("Lower Colorado ") 
Formation
Dakota 
Member
 
Submember
 
Start Depth
482.00 ft
End Depth
614.00 ft
Contact Accuracy
Contacts Poorly Defined Or Complete Gap 
Penetration
Complete Penetration, No Gaps 
Primary Lithology
Shale 
Percent
Secondary Lithology
Sandstone 
Percent
Tertiary Lithology
 
Percent
Comments
Start Depth: 614.00 ft
End Depth: 675.00 ft
Unit: Sioux Quartzite 
System
Proterozoic 
Series
 
Group
 
Formation
Sioux Quartzite 
Member
 
Submember
 
Start Depth
614.00 ft
End Depth
675.00 ft
Contact Accuracy
Unknown 
Penetration
Unknown 
Primary Lithology
Sandstone 
Percent
Secondary Lithology
Unknown 
Percent
Tertiary Lithology
Unknown 
Percent
Comments