30 



PHYSIOGRAPHIC GEOLOGY. 



then returning again more or less nearly to their former course, and 

 that the peaks of a ridge are very far from being in an exact line 

 even over a short course ; again, that several approximately parallel 

 courses make up a chain. 



A. Northwesterly system of trends. — In the southwestern 

 Pacific, the New Hebrides (Fig. 23) show well this linear arrangement; 

 and even each island is elongated in the same direction with the group. 

 This direction is nearly northwest (N. 40° W.), and the length of the 

 chain is 500 miles. New Caledonia, more to the southwest, has 

 approximately the same course, — about northwest. Between New 

 Hebrides and New Caledonia lies another parallel line, the Loyalty 

 Group. The Salomon Islands, farther northwestward, are also a linear 

 group. The chain is mostly a double one, consisting of two parallel 

 ranges; and each island is linear, like the group, and with the same 

 trend. . The course is northwest-by-west, the length 600 miles. 



In the North Pacific, the Hawaian range has a west-northwest 

 course. The Sandwich or Hawaian Islands (Fig. 24), from Hawaii to 



Fig. 23. 



Kauai, make up the southeasterly part of the range, about 400 miles 

 in length. Beyond this, the line extends to 175° E., making a total 

 length of nearly 2,000 miles, — a distance as great as from Boston to 

 the Great Salt Lake in the Rocky Mountains, or from London to 

 Alexandria. Moreover, in this chain, there are on Hawaii two sum- 



