756 



(JKOLOGY 



During the closing stages of the Upper Cretaceous, fresh-water beds 

 appear in localities (alpine region) where marine sedimentation had 

 been in progress earlier in the period, showing that the movements 



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J Ct- 



\l 



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V* 



5^=7 



rrs 



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r 



^% :> xV^'^l^feM^^"^ < 



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Fig. 512. Map and section showing relations of igneous rock to tin- Cre- 

 taceous formations in the Crazy Mountains of Montana. The section 

 is along the line AB of the map. Klv, Livingston format ion: <li, diorite; 

 gr, granite. The especial feature of the map is the extraordinary mun- 

 l.cr of dikes radiating from the central intrusion, <li. The shaded area 

 about di represents the zone of contact metamorphism aboul the m- 

 trusidn. Length of section ahout 20 miles. (Livingston and Little 

 Belt, Mont., folios, U. S. Geol. Surv.) 



