DETAILED STRATIGRAPHIC DISTRIBUTION. 



143 



Detailed 



hie distribution of Cambrian and Ordovician Brachiopoda — Continued. 

 Ontario, 



See Quebec, Ontario, and Labrador for general discussion of stratigraphy. 



Pennsylvania. 



All but two of the Pennsylvania localities (see index for numbers) are from approximately the same horizon in the 

 Lower Cambrian. One locality (346b) is from the Tapper Cambrian and one (48d) from the Middle Cambrian. 



Quebec, Ontario, and Labrador. 



Thi'ee general horizons fi'om Quebec and Ontario are represented in the collections: An Ordovician (Chazy?'), an 

 Upper Cambrian equivalent to the Potsdam of New York, and a Lower Cambrian in limestone pebbles in a conglomer- 

 ate. The Lower Cambrian forms may be compared with those occm-ring in localities 392a, 392c, and 3921, all at the 

 Straits of Belleisle, Labrador. See index for numbers of all localities in Quebec, Ontario, and Labrador. 



Localities and species. 



I Four drilt bowlders found in East Prussia (localities 3861-1) are included. 



