360 



THE CAMBRIAN. 



Classification of the formations. 



[BULL. 81. 







Lower Cal- 



Lower portion of the Calciferous sandrock of New York and Canada; Lower 







ciferous. 



Magnesian limestone of Wisconsin, Missouri, etc. 



' 





( 



Type. 



Sandstones of the north and east sides of the Adirondack s Mountains of New 

 York and adjoining parts of Canada. 



Correlated. 





q 





Limestones of the south side of the Adirondacks and Dutchess County, New 





<3 





York, and an unknown portion of the limestones of the "Marble Belt" of 





a 





western Vermont. 





eg 



o 



Potsdam. < 



Shales of Tennessee (Knox), G-eorgia, and Alabama (Connasauga). 









Sandstones of the Upper Mississippi Valley (St. Croix), South Dakota, Wyo- 









ming, Montana, and Colorado. 





p 





Sandstones and calcareous beds of northern Arizona (Tonto) and central Texas 



(Katemcy). 

 Limestones and shales of Nevada (Hamburg), Idaho, and Montana (Gallatin). 

 Black shales of the upper portion of the New Brunswick and Cape Breton 



Island sections. 

 Shales and sandstones of Conception Bay, Newfoundland (Belle Isle). 









Type. 





a 

 .2 





Shales and slates of eastern Massachusetts (Braintree), New Brunswick (St. 



a 



,0 



a 





John), and eastern Newfoundland (Avalon). 





OS 



Acadian. < 



Correlated. 



S 

 3 

 O 







Limestones of Dutchess County, New York (Stissing), and central portions of 



s 





Tennessee and Alabama sections (Coosa). 









Limestones of central Nevada and British Columbia (Mount Stephen). 







I 



Type. 



Shales and limestones of western Vermont (Georgia) and Red Sandrock. 



Correlated. 



Quartzite of western slope of Green Mountains (" Granular Quartz ") and Ap- 

 palachian Range of Pennsylvania, Virginia, Tennessee (Chilhowee), Georgia, 





►a 





and Alabama. 









Shales with interbedded limestones and rooting slates of southern Vermont, 





a 



O 



Georgian. < 



New York, and south to Alabama. 

 Limestone, sandstone, and shales of Straits of Belle Isle (Labrador), northwest 









coast of Newfoundland, and peninsula of Avalon (Placentia). 





o 



h3 





Basal series of Hanford Brook Section, Caton's Island, etc., New Brunswick 



(Ifanford). 

 Shales and limestones of eastern and southeastern Massachusetts (Attlebor- 



OUgll). 



Lower portion of Eureka and Highland Ranges, Nevada (Prospect). 

 Portion of Wasatch Cambrian section (Cottonwood). 



I 







Base of Castle Mountain limestone, British Columbia (Castle Mountain). 



