page 5 
3. Claystone, silty, becoming shaly, black; 
some irregular interbeds clayey silt- 
stone. Grades to unit 4 above, becomes 
sandy at base. 
5. 5* 
Lakota formation (in part) 
2. Sandstone, fine- to coarse-grained, with 
some conglomeratic beds; massive, cross- 
bedded, weathers reddish brown. Upper 
1. 0 to 1. 5 feet is capping interval with 
sandstone at top, a middle layer of light 
gray gritty claystone and a basal 1 foot 
layer of red ferruginous, locally con- 
glomeratic sandstone. 24.4’ 
1. Claystone, slightly silty, gray, subcon- 
coidal fracture. 0.4 - ? 
Obscured by slope wash. 
Total thickness of Fall River (rounded) = 164 feet 
Supplemental section showing details of the 
Lakota contact about 200 feet southeast of 
the old quarry gulley locality. 
Descending 
Thickness in feet. 
E. Dark gray clayey to shaley siltstone 
equivalent to unit 3 of preceding 
section. 
1. 5 - ? 
