Chapter IV. 



MIDDLE AND UPPER ORDOVICIAN. 



Color, light bluish purple. 



Symbol, 17. 



Distribution: General throughout the continent. In the Arctic mapped with the Silurian; in 



the Rocky Mountains of the United States included in narrow bands of Cambrian and 



lower Ordovician. 

 Content: Early to uppermost Ordovician (Chazy to Richmond, inclusive). 



Middle and upper Ordovician areas. 



Page. 



H 13 Texas (mapped in part with. Silurian) 158 



1 12-13 Arizona and New Mexico (mapped largely with Cambrian) 158 



I 14 Oklahoma 159 



1 15 Arkansas 160 



1 16 Alabama, Georgia, and southeastern Tennessee 164 



I-J 16-17 Ohio, Kentucky, and Tennessee 165 



J 11-12 Great Basin, Nevada and Utah 168 



J 13 Southern Colorado and New Mexico (mapped with Cambrian) 169 



J 15 Northern Arkansas (mapped with Cambrian) 169 



J 15-16 Missouri and southern Illinois 169 



J 16 Indiana 171 



J 17-18 Maryland, Virginia, and east Tennessee 173 



K 10 J Taylorsville district, California (mapped with Devonian) 175 



K 12 Wasatch and Uinta ranges, Utah (mapped with Carboniferous) 175 



K 13 Black Hills (mapped with Cambrian) '. 176 



K 16 Southeastern Wisconsin and northeastern Illinois 176 



K 17-18 Pennsylvania and New Jersey 176 



K-L 12-13 Wyoming and northern Colorado (mapped witli Cambrian)'. 179 



K-L 15 Minnesota, northeastern Iowa, southwestern Wisconsin, and northwestern Illi- 

 nois 180 



K-L 17-18 Ontario and New York : 183 



K-L 18-19 Vermont, New Hampshire, Massachusetts, and Connecticut east of the Green 



Mountains (not mapped) 192 



L 12 Southwestern Montana (not mapped) 194 



L 16 Upper Peninsula of Michigan 194 



L 17 Manitoulin Islands; Lake Nipissing, Lake Temiscaming, and Mattawa on the 



Ottawa (not mapped) I95 



L 18-19 St. Lawrence Valley, Carleton and York counties. New Brunswick (mapped 



with Cambrian) 19g 



M 11 Beaverfoot Range, Canadian Rocky Mountains (not mapped) 207 



M 19-20 Gaspe Peninsula; Mingan and Anticosti Islands 208 



M 21 Newfoundland, northern peninsula (not mapped) 211 



M-N 14 Lake Winnipeg district, Manitoba 217 



9 ^ Dease River, British Columbia (not mapped) 219 



O 15 Southwest coast of Hudson Bay 220 



P-Q 3-7 Alaska (not mapped) 221 



P-Q 17-19 Southampton Island, Fox Land, and Ungava Bay (mapped with Silurian) 221 



Q 3 Seward Peninsula (mapped with Cambrian) 222 



R-T 10-20 Arctic Archipelago (mapped with Silurian) 222 



S 27 Eastern coast of Greenland 224 



156 



