210 r. B. TAYJ.OR OKIGIN OF THE EARTHS PLAK 



way was once united to the east coast of Greenland, although they are 

 now over 1,000 miles apart, and the same may have been true of the 

 northwest sides of Scotland and Ireland. There is less reason to think 

 that the rifts on the sides toward Eurasia are wholly of Tertiary age; 

 they may have been made partly at an earlier time, as suggested by Suess. 



It may be noted that the greatest breadth of the Arctic Ocean, and 

 probably of the parting from Greenland, is toward Asia, including tlie 

 Aleutian arc. It is widest toward the island arcs of eastern Asia and 

 toward the Malay earth-lobe and India. In figures 6 and 7 one can 

 scarcelv fail to see that the western coast of i^^orth America shows only 

 faint, incipient arcs, corresponding to less crustal movement and the rela- 

 tively narrow rift on the west side of Greenland, while on passing to the 

 east coast of Asia the great island arcs bulge boldly into the depression of 

 the Pacific, corresponding to a much more vigorous crustal movement 

 and to a much wider rift between Greenland and Asia. 



It is thus seen that the idea of a general crustal creep from high toward 

 loAv latitudes in the northern hemisphere is borne out, not alone by the 

 peripheral mountain ranges which fringe the southern border of Eurasia 

 and the southwestern border of North America, but also by a rifting and 

 pulling away of the earth^s crust on all sides of Greenland, and that the 

 amount of pulling away is least toward the feebler peripheral ranges and 

 greatest toward the stronger. 



The following are the faint peripheral arcs of North America: (1) 

 The Alaskan Island arc, comprising the island chain of southeastern 

 Alaska with Queen Charlotte and Vancouver Islands; (2) the Coast 

 Eange arc, extending from the Strait of Juan de Fuca to southern Cali- 

 fornia, and (3) the Mexican arc, extending through Lower California and 

 southern Mexico to the Isthmus of Tehuantepec. These arcs are shown 

 in figure 7, but they are all faint and of slight curvature. Tliey show 

 much better in a map of Korth America drawn on spherical projection. 



Suess has much to say concerning the remarkable correspondence of 

 the Paleozoic and older sediments, and also of the mountain ranges on 

 the two sides of the North Atlantic, He describes "The North Atlantic 

 Continent" at some length (II, 220-355), and shows that it persisted 

 until a very recent time in the earth's history. "We have recognized the 

 existence of two continents, of which fragments only are visible at 

 the present day. The first occupied the position of the north Atlantic 

 Ocean, as is indicated by the nature and distribution of the Paleozoic 

 sediments in Europe and America ; Greenland is a remnant of it. This 

 ancient continent is the Atlantis" (II, 254). Suess dwells upon the 

 likeness of the Carboniferous sediments as being especially remarkable. 

 The other fragmental continent referred to is Gondwana-land. 



