14 INDEX TO THE STRATIGEAPHY OF NORTH AMERICA. 



Content: In Canada, sandstones and lava flows that are little disturbed or altered but have no 

 fossils, "Cambrian" of Canadian reports, sometimes tentatively correlated with the Kewee- 

 nawan series or with the Animikie group (Upper Huronian) ; Athabasca-Nastopoka series 

 of Adams; gold-bearing Meguma series of Nova Scotia; Random and older formations of 

 the Avalon group of Newfoundland; quartzites of Uinta and Wasatch ranges of Utah 

 (mapped under Belt series); Needle Mountains group of Colorado (mapped under Belt 

 series)'. 



BELT SERIES. 



Color, light brown. 



Symbol, 21a. 



Distrihution: Western Rocky Mountains of Idaho, Montana, British Columbia, and Alberta. 



Content: The Belt series (late Algonkian) of Idaho, Montana, British Columbia, and Alberta. 

 (The quartzites of the Uinta and Wasatch mountains of Utah and the Needle Mountains 

 group of Colorado, which are regarded as possible equivalents of the Belt series, have also 

 been included under this color on the map, as has the Cherry Creek group of Montana, 

 which is probably of early Algonkian agq.) 



KEWEENAWAN. 



Color, light brown with red dashes. 



Symbol, 21b. 



Distribution: Lake Superior region, Ontario, Minnesota, Wisconsin, and Michigan. 



Content: Keweenawan lava flows and sediments, within the area known to be of Keweenawan 



age; also "Nipigon" series, but not including possible equivalents in other districts. Areas 



mapped include intrusive igneous rocks. 



TTPPEB HURONIAN (OF THE LAKE SUPERIOR REGION). 



Color, brown (vertical ruling) . 

 Symbol, 21c. 



Distribution: Lake Superior region; Ontario, Minnesota, Wisconsin, and Michigan. 

 Content: Animikie and equivalents in the Lake Superior region only. Areas mapped include 

 iutrusive igneous rocks. 



EARLIER (?) PRE-CAMBRIAN (UNCLASSIFIED, MUCH ALTERED). 



Color, brown with white dashes. 



Symbol, 22. 



Distribution: Canada in general outside of the districts specially classified; Nova Scotia and 

 Newfoundland ; Cherry Creek group of Montana (probably of early Algonkian age, mapped 

 under Belt series, late Algonkian) . 



tContent: Metamorphosed sediments and volcanics, in places richly iron bearing, widely dis- 

 tributed throughout the Canadian shield, and commonly classed as "Huronian;" in Mon- 

 tana the Cherry Creek group (probably early Algonkian), which is mapped under Belt 

 series, late Algonkian. 



HASTINGS AND GRENVILLE. 



Color, dark reddish brown. 



Symbol, 22 a. 



Distribution: Eastern Canada, Ontario, and Quebec; probably present but not distinguished 



on the map in Adirondack region. New York. 

 Content: Limestone and associated rocks of the Hastings and the Grenville series in the type 



areas. 



