444 HISTORICAL GEOLOGY. 



(2) Farther east, from near Chaleur Bay, on the Gulf of St. Lawrence, 

 through New Brunswick, southwest to the coast of Maine (including the 

 Mount Desert rocks) and into eastern Massachusetts. (3) The Acadian 

 Eange, along western Newfoundland and central Nova Scotia ; then sub- 

 merged off the coast of Maine and Massachusetts ; then over southeastern 

 Massachusetts, and probably along Long Island. (4) A central Newfound- 

 land range, which may have had a submarine extension along Sable Island 

 and the shoals about it, east of Nova Scotia. (5, 6) Two other ranges 

 farther east. 



The Acadian is the longest of these Archsean ranges ; it is the chief eastern 

 belt of the Archaean on the Atlantic border, and is strictly the Acadian pro- 

 taxis. Its partial submergence is not in doubt ; for besides indications of 

 this along the sea-bottom south of Nova Scotia, there is proof of subsidence 

 of several hundred feet in the fiords of Maine and the coast; in the Bay 

 of Fundy, in Massachusetts and Narragansett bays, and in Long Island 

 Sound. The combination of the Acadian and Appalachian protaxes deter- 

 mined the existence of the great "Middle Bay" of the Atlantic Coast (page 

 210), and in the region of their junction lies the bay of New York with 

 the mouth of the Hudson. Thus the foundations were laid in Archaean 

 time. 



On the Pacific border, northivestward in general trend. — The chief Archaean 

 ranges on the Pacific border are the following : (1) The Rocky Mountain 

 protaxis, or the " backbone " of the mountains. It extends northward and 

 westward nearly to 53° N., in the Peace River region, and is represented be- 

 yond in isolated areas. It bends eastward 250 miles south of 49° N., and then 

 extends southward and westward through Colorado into New Mexico. The 

 region of the bend, whence go off eastward and westward several of the large 

 rivers of the continent, is the locality of the Yellowstone Park. Along the 

 west side of the Wasatch Range, near Salt Lake, the Archaean areas appear 

 to be parts of a western spur of the protaxis, nearly in a line with the part 

 of it in British America. To the westward are other nearly parallel Archaean 

 ranges, in the Great Basin ; along the Sierra Nevada in California and in the 

 Sierra Madre of western Mexico ; and probably in the Coast and Island 

 belts of British America. In addition, isolated areas occur east of the Rocky 

 Mountain chain in the Black Hills of Dakota, the Iron Mountain region of 

 Missouri, and in central Texas. Thus the oldest land areas marked out 

 well the outlines of the continent. 



There is a landward bend in Pennsylvania of the Appalachian protaxis, 

 like the landward bend of the Rocky Mountain protaxis, and the two bends 

 are not much south in latitude of the southern end of the nucleal Archaean 

 area of the continent ; as if connected in origin with the absence farther 

 south of outcropping Archaean. 



Archaean rocks are the prevailing rocks of the portions of Greenland free 

 from its covering of ice, and they make a large part also of Baffin Land, on 

 the opposite side of Baffin Bay. 



