CHAPTER X. 



AREAL GEOGRAPHY OF NORTH AMERICA IN THE LATE 



PALEOZOIC. 



As suggested in an earlier paper and in other portions of this work, the 

 geography of North America was undergoing a progressive change during 

 the latter part of the Paleozoic, and no one place or period can be considered 

 as typical of the whole. Certain areas, however, are fixed for the whole 

 time. The Paleozoic continent of Appalachia extended far to the east 

 of its present exposure and for some undetermined distance beyond the 

 present coast-line of the Atlantic. There can be no doubt that for a portion 

 of the time some part of this continent was a high and rugged land. To the 

 west of this land lay the sinking area containing the coal basins of the 

 Pennsylvanian period, which was slowly filled in the latter half of that period, 

 coincident with and dependent upon the elevation of Appalachia. 



The same condition of depressed land with accumulation of swamp ma- 

 terial existed to the northeast through eastern New England and the Mari- 

 time Provinces of Canada even to Prince Edward Island, but it is possible 

 that this northeastern area continued to the south, somewhat to the east, 

 and independent of the basin area in Pennsylvania and West Virginia. 

 The southern extension of the Boston and Rhode Island Basins was very 

 probably directly to the south, and such sediments as may now be preserved 

 are beneath the surface of the ocean. 



South of West Virginia and Kentucky the surface of the eastern part of the 

 United States was above the plane of deposition and no record is preserved. 



The great area including western Pennsylvania and West Virginia 

 stretched away to the west as far as the eastern border of the uplift in 

 central Missouri. It was broken by the elevated land around the Cincinnati 

 uplift, but the series of beds may, in part, be traced through the portion of 

 Kentucky to the south. The southern peninsula of Michigan was at this 

 time probably in the last stages of the formation of the upper coal beds of 

 that State. 



The elevated area in Missouri was subjected to partial invasion by local 

 seas from Illinois and from Kansas in late Pennsylvanian time, but soon 

 became dry land, and during all of the Permo-Carboniferous was out of 

 water and undergoing erosion. It is very probable that through all of the 

 late Paleozoic there was a land area north of Missouri which reached up to 

 the southern edge of the Canadian shield. 



253 



