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GEOLOGY. 



These groups are readily separated and distinguished on the up- 

 per Missouri and through Nebraska, except along the Republican 

 River. Had I first studied the Cretaceous on the Republican, 

 Meek and Hayden v s divisions would have appeared inapplicable as 

 these groups there shade into each other. The geologist, however, 

 who first studies the rocks of this period on the Missouri cannot 

 well deny the validity of this grouping. Since the rocks of this 

 period have been studied in the mountains by the United States 

 Surveys, two of the chiefs, Clarence King and Dr. Hay den, have 

 agreed on a slightly different division. They retain No I, or the 

 Dakota Group as the basal member of the series. The next three ? 

 however, namely, the Fort Benton, Niobrara, and Fort Pierre 



