DIFFERENT PROVINCES OF NORTH AMERICA IN LATE PALEOZOIC TIME 49 



The break between the Eastern Province and the Plains Province is 

 formed by the Missouri Island and between the Plains Province and the 

 Basin Province by the Rocky Mountain Barrier. Both of these breaks 

 may be less important from the fact that the beds may be traced around 

 their northern or southern edges almost or completely to an actual connec- 

 tion. The northern limits of both the Plains and the Basin Provinces are 

 not yet known, but it is very possible that both may be traced north of the 

 United States-Canadian boundary. The break between the Basin Province 

 deposits and the deposits of the British Columbia-Alaska-Pacific Coast area 

 is only partially bridged at present, but this is of less significance, as the 

 deposits of the last-named area are all proven with fair certainty to be below 

 the level of red-bed deposition and are discussed in this work because of 

 their bearing upon the general question and the possible routes of migration. 



The correlations given in table i , for the Eastern and the Plains Prov- 

 inces, show no considerable departure from the published and accepted corre- 

 lation tables, except possibly in the New England and Canadian regions. 



The position of the Carboniferous and Permo-Carboniferous deposits of 

 the Massachusetts and Rhode Island areas is very uncertain. As shown in 

 the summary description of the stratigraphy, the Cambridge slate and the 

 Squantum tillite member of the Roxbury conglomerate are considered to be 

 post-Pennsylvanian, and the Dighton conglomerate is regarded as of the same 

 age, but the evidence for this is at best uncertain; these deposits may be 

 much earlier. The New Glasgow conglomerate is certainly post-Joggins in 

 age and in all probability close to the uppermost Massachusetts and Rhode 

 Island deposits in stratigraphic position. The conglomerate beneath the red 

 shales and sandstones of Prince Edward Island occupies a similar position. 



The position of these four series in the correlation table is therefore only 

 provisional, and there seems no reason why they might not have been much 

 lower, for it is very possible that the same disturbances which originated 

 the deposition of red beds in West Virginia and Pennsylvania might have 

 caused the glaciatiqn southeast of the Boston Basin and the elevation of the 

 Cobequid Hills. 



A. THE EASTERN PROVINCE. 



The coal regions of West Virginia and Pennsylvania may be taken as 

 the type regions of the province. A list in sequence of the principal layers 

 of the upper Pennsylvanian and Permo-Carboniferous of these regions is 

 given in the correlation table opposite page 48. Details of these forma- 

 tions, additional to those given below and in Publication No. 207 of the 

 Carnegie Institution of Washington, may readily be found in the excellent 

 reports of the geological surveys of West Virginia (coal reports), Pennsyl- 

 vania, and the United States, and in the pages of the bulletin of the 

 Geological Society of America.^ 



' Notably Stephenson, J. J., Bull. Geol. Soc. Amer., vol. 18, pp. 29-178, 1907. 



