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Type section of the Fall River formation 
Pieced from exposures in the bluffs of Fall River in 
the area of the falls and of Evan* s Quarry which is on 
the south side of the river just above the falls. All 
exposures lie in the Nl/2, sec, 33, T, 7S. , R. 6E. , 
Hot Springs quadrangle, Fall River County, South 
Dakota, Unit 7, the Evan's Quarry sandstone of 
Russell (1928), was measured on the bluff above the 
road to Buffalo Gap about 900 feet from its inter- 
section with U, S, Highway route 18; units 3 through 6 
were measured in a gulley, draining an old quarry, 
which crosses Buffalo Gap road about 500 feet from 
the intersection; and additional details of the contact 
described in the supplement were observed about 
200 feet southeast of the gulley along Buffalo Gap 
road. That part of the Fall River above the Evan's 
Quarry sandstone, units 8 through 22, was measured 
from continuous exposures on the northeast side of 
the river from the foot of the falls southeastward to 
the bluffs of Skull Creek shale opposite the Power 
Plant. 
Skull Creek Shale (basal part) Thickness in feet. 
22, Shale, and silty shale, black, 
scattered ironstone concretions 
in upper 0. 5, Basal 1. 5 is 
tough black argillaceous silt- 
stone with rusty stain. 4. 0' 
21. Shale, black, silty. Lower half 
siltier with pink stain. 2. O' 
