'258 J. B. WOODWORTH APPxlLACHIANS IN NEW ENGLAND 



abundance of late Cambrian brachiopodS;, and two pebbles have been 

 found, one in situ, the other in the drift on Marthas Vineyard, carrying 

 a Spirifer like that of the Lower Devonian Chapman sandstone of Maine. 

 From this fragmentary evidence it is inferred that strata as old as the 

 Lower Devonian were exposed to erosion in Alleghenian time in this lost 

 land, now a part of the existing coastal shelf. 



The westwardly dipping schists along the Atlantic coast from southern 

 Maine southward across Maryland and North Carolina, as seen beneath 

 the cover of Mesozoic and Cenozoic strata along the inner edge of the 

 coastal plain, support the view of a widespread overturning of structure 

 toward the southeast, or, in other words, toward the present Atlantic 

 basin. This is in marked contrast with the general westward overturning 

 of structure on the western border of the Appalachian mountain belt, 

 "whatever difference there may be in the age of the diastrophic movements. 



In the eastern part of the section across Massachusetts, intrusive and 

 ■extrusive phenomena took on a noticeable development during the later 

 Paleozoic phases of deformation. Therefore, during Pennsylvanian time, 

 erosion and deposition were introductory to the mountain-building and 

 vulcanism in this Acadian field. 



On the iVvalon peninsula, at the southeastern extremity of Newfound- 

 land and eastward of the line of strike of the folded Carboniferous strata 

 of Cape Breton and southeastern Massachusetts, Cambrian strata dip 

 .gently seaward along the shore of Marys Bay. These beds appear to 

 form a remnant of the tilted Paleozoic strata on the eastern border of 

 the Acadian mountain belt, from southern New England northeastward 

 through southern Newfoundland. The New England section of Acadian 

 structure, from the mouth of the Hudson Eiver eastward to the head of 

 Buzzards Bay, is cut off on the south by the sea. South of this area, the 

 southern equivalent of Acadia, the eastern portion of the Appalachian 

 :mountain belt, lies concealed beneath the Mesozoic and later strata of the 

 coastal plain. From Alabama to Newfoundland the curvilinear strikes 

 of the geological structure are reflected in the great curving bights of the 

 coast and its projecting capes. The Precambrian and all later Paleozoic 

 rocks bear one pervading sinuous structure, impressed on them in the 

 closing Paleozoic episode of mountain-building, as if the ranges were 

 shortened from northeast to southwest by gigantic bendings in a hori- 

 zontal plane transverse to their longitudinal extension. These great 

 bends in the larger structure of the eastern border of North America, 

 alternately northwestward and southeastward, characterize a complex 

 Paleozoic mountain system in which the western margin displays quite 

 uniformly a westward outflow of rock, while its eastern margin — imper- 



