SEDIMENTARY ROCKS 



469 



Columnar Sections 



IN THE. 



5we:et Grass Hills 



MOMTANA 



Vertical 5c3\e, lln = ^00 Ft 



MONTANA-CANAOIAN 

 WELL N^o 



INTERNATIONAL BOUNDARY 

 WEST BUTTE* 



MONTANA-CANADIAN 



WELL N4 4 

 North of IVhillash 









FiuruK S.—Colininuir tSettioim hi the Hircet Oniff.s Hills, .Votihiim 



