Lakota f orraa t ion 
Thickne s s 
no 
Clays t one , waxy, gray 
above becoming silty 
to light gray, soft 
and tougher downward* 
21 
J- « 
Clay stone, silty , variegate d, tough in upper 
part becoming silty softer downward, grad- 
ational with units above and below# Chief- 
*• 
ly red and re dbrown, mottled with green in 
lower foot and with purple and green in 
apperl.5 foot* 
4~ QT 
* > 
UW o 
lays tone and shale. Cppcr 3*-' chiefly 
greenish gray silty clays tone; basal 1.5 ' 
soft waxy shale, probably bentonitic, 
light grayish green. 
' -u w 
c n t 
J O 
19. 
Sandstone, fine-grained, thin-bedded, 
cross-laminated, micaceous; thin interbeds 
light gray shale. B e ddin % with rroole- 
w Q «/ ** 1 ^ * 
marks and’’worm ?? tracks. Weathers light 
gray to yellow gray. 
o /: | 
*> * o 1 
-i r> 
! /*r 
Shale, lisht grav, weathers yellowish to 
olive gray. 
5 
O f 
