386 



INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



iferous" the two formations known as the Union and Riversdale, which had been 

 classed as Devonian on stratigraphic grounds. He sums up his conclusion in a 

 table as follows : 



Formations of the Carboniferous of a portion of Nova Scotia. 



Formations. 



Neo-CarboniferouS' 



Cape John 



Pictou 



Smelt Brook... 

 Small'a Brook. 

 New Glasgow.. 



fStellarton. 



Meso-Carboniferousp^^*^ll« 



Hopewell. 

 I Windsor. . 



Eo-Carboniferoua-j 



Union 



Riversdale. 



Northern areas. 



Cape John sandstones 



Pictou freestones 



Smelt Brook shales 



Spirorbis limestones 



New Glasgow conglomerates. 



Unconformity. 



rMillstone grit 



Unconformity - 



Southern areas. 



Coal Measures. 



Millstone grit 



I Unconformity (?) 



Hopewell and Windsor. 



Union 



Riversdale. 



:} 



Order. 



XII. 



XI. 



X. 



IX. 



VIII. 



VII. 



VI. 



V. 



IV. 



III. 



II. 



I. 



In placing the Union and Riversdale at the base of the Carboniferous Ami 

 accepted Fletcher's determination of their stratigraphic position below the lower 

 Carboniferous limestone. Subsequent field study led him to recognize the fact 

 that the limestone is overthrust upon these formations and normally belongs below 

 them. He then accepted the evidence of the fossils, which places them in the 

 "Meso-Carboniferous."'' (See pp. 330-331.) 



L-M 11-12. WESTERN MONTANA AND NORTHERN WYOMING. 



Near the intersection of the forty-ninth parallel with the one hundred and 

 fifteenth meridian, just west of the Flathead Valley, Montana, Carboniferous lime- 

 stone of St. Louis age was identified by Weller.^*'"' It rests conformably upon a 

 pure quartzite, 25 feet thick, which lies unconformably, though without marked 

 angular discordance, upon pre-Cambrian argillite of the Belt series. The exten- 

 sion of this formation in the McDonald Range of southern Alberta has been noted 

 by Leach '^^ under the general term " Devono-Carboniferous." 



On the headwaters of Teton River, a branch of the Missouri, in latitude 48°, 

 Carboniferous limestone forms the eastern portion of the Rocky Mountains between 

 the Great Plains (Cretaceous) and the central ranges (Belt series, Algonkian). 



In the Belt Mountains and other ranges of southwestern Montana and northern 

 Wyoming the Carboniferous is represented, according to Weed, and others, by Madi- 

 son limestone and Quadrant quartzite. The type locality from which they were 

 described by Peale is in the Gallatin Valley near Three Forks, Mont. Peale®^'* 

 summarized the section. Girty ^'^^ has since discussed the fauna and correlation 

 of the Madison limestone under the heading "Lower Carboniferous," as follows: 



The Madison limestone has been divided by the geologists of the Survey, upon hthologic 

 characters, into nine beds, ranging from 24 to 32, both inclusive, of their section scheme. The 

 following table, representing in condensed form the stratigraphic succession ascertained in the 



