732 DYNAMICAL GEOLOGY. 



VII. The continents and oceans had their general outline or 

 form denned in earliest time. This has been proved with regard 

 to North America from the position and distribution of the first 

 beds of the Lower Silurian, — those of the Potsdam epoch. The 

 facts indicate that the continent of North America had its surface 

 near tide-level, part above and part below it (p. 196) ; and this will 

 probably be proved to be the condition in Primordial time of the 

 other continents also. And, if the outlines of the continents were 

 marked out, it follows that the outlines of the oceans were no 

 less so. 



VIII. The prevalent courses of coast-lines, mountain-chains, and 

 groups of islands over the globe are two, — one between the north- 

 east and southwest, and the other between the northwest and 

 southeast (p. 30). 



IX. In the courses of the earth's outlines, while there are two 

 prevalent trends, there are very commonly curves : — in some cases 

 a gradual curve, as from E.N.E. to N.N.E., as in the great central 

 chain of the Pacific, or from N.E. to E. and then to N.N.E., as in 

 the line from New Zealand to Malacca (p. 32) ; in others, a series 

 of several curves, meeting one another nearly at right angles, as 

 in the island-ranges off the Asiatic coast (p. 36). 



X. The earth towards or about the equatorial regions is belted 

 with oceanic waters separating its northern and southern conti- 

 nents, passing through the East Indies, Eed Sea, Mediterranean, 

 and "West Indies ; and this region is remarkable for its volcanoes 

 (p. 686). 



The preceding are some of the comprehensive characteristics of 

 the globe which exhibit the system that pervades its physiognomy 

 and illustrate the manner in which this system was educed. 



2. Deductions from the positions of the reliefs. 



1. The situation of the great mountain-chains, mainly near the 

 borders of the continents, does not indicate whether the elevating 

 pressure acted within the continental or oceanic part of the earth's 

 crust. But the occurrence between the principal range and the 

 sea-coast of the larger part of the volcanoes (and, therefore, of the 

 profound and widely-opened fractures) of these borders, of the 

 most extensive metamorphic areas, and the closest and most nume- 

 rous plications of the strata, as so well shown in North America, 

 are sufficient evidence that the force acted most strongly from the 

 oceanic direction. 



2. The relation between the extent of the oceans and the height 

 and volcanic action, etc. of their borders proves that the amount 



