Chaptek III. 



CAMBRIAN AND LOWER ORDOVICIAN. 



Color, purplish red. 



Symbol, 18. 



Distribution: General throughout the continent. (See fig. 5.) 



Content: In general comprises Lower Cambrian (Georgian) to Lower Ordovician (Beekman- 

 town), inclusive, or so much as may be present; in the Appalachian zone, Virginia to 



Alabama, includes conformable formations below the Olenellus horizon; Ocoee group and 

 other terranes; Brevard, Weverton, Harpers, and others not named. In the Cordillera 

 includes upper Ordovician and Silurian where they are present and the bands of color 

 are too narrow for distinct mapping. 



Cambrian and lower Ordovician areas. 



Page. 



H 12 Bisbee district, Arizona 72 



H 13 Trans-Pecos Texas 75 



H 14 Llano district, Texas 77 



1 12 Arizona 81 



1 13.. New Mexico (not separately mapped) ■ 81 



1 14-15 Oklahoma 82 



1 16 Alabama and Georgia, 84 



I-J 12 Grand Canyon, Arizona 88 



I-J 16-17 Tennessee and North Carolina 89 



J 11-12 California, Nevada, and Utah 98 



J 13 Colorado 102 



J 15 Missouri and northern Arkansas 103 



J 17-18 Virginia and Maryland. (See J 17-18, Chapter IV, pp. 173-175.) 



K 12 Idaho and Utah 106 



K 18 Pennsylvania, New Jersey, and slate belt of eastern New York and western 



New England 107 



K 19 Eastern Massachusetts 114 



K-L 12-13 Wyoming 116 



K-L13 Black Hills, South Dakota '. 118 



K-L 15-16 Minnesota, Wisconsin, and Michigan 118 



K-L 18 Adirondack region. New York 120 



L 12 Southwestern Montana ; 127 



L 18-19 St. Lawrence Valley _.. 130 



L 19 Maine; Carleton and York counties, New Brunswick 134 



L 20-22 New Brunswick, Cape Breton, and Newfoundland 136 



L-Q 10-21 Cana'dian shield 148 



M 19-20 Gaspe Peninsula 148 



M 21 Northern Newfoundland 149 



M-N 11 Rocky Mountains of Canada 154 



Q 3 Seward Peninsula. (See O-R 2-8, Chapter VII, pp. 353-354.) 



Q 5-6 Northern Alaska. (See O-R 2-8, Chapter VII, pp. 353-354.) 



8 27 Eastern coast of Greenland. (See Chapter IV, p. 224.) 



T 17-18 Ellesmere Land I55 



H 12. BISBEE DISTRICT, ARIZONA. 



In southeastern Arizona, in the Bisbee district, Ransome ®^^ distinguishes the 

 probable equivalents of the Tonto group as the Bolsa quartzite and Abrigo lime- 

 stone. He says : 



72 



