450 GEORGE ROGERS MANSFIELD 
9 oO 
bd iy ~ . 
SN Oa Ss NSN 
Ne SAGA NALD 
SSSRQESo> <s S NS . 
OANA SS 
Ny, 
Q . x . x . 
SOs 
SSS 
Cretaceous 
and Jurassic 
Triassic 
(Uneluding Nugget sandstone, 
Jurassic) : ‘ 
0 
: 3 
ce Permian a 
° a 
A g 
Cmp ss 
< 
o. 
Pennsylvanian | 
and Mississippian 
5 Miles. 
Fic. 3.—Map with geologic structure section of “swallowtail” folds in adjacent 
parts of the Slug Creek, Crow Creek, and Montpelier quadrangles, showing the folding 
and erosion of the plane of the Bannock overthrust, U.S.G.S. 
