34 PHYSIOGRAPHIC GEOLOGY. 



(a.) The chain, as is seen, consists of a series of parallel ranges 

 succeeding and overlapping along the general course, in the manner 

 illustrated on page 19, when speaking of mountains, (b.) It varies 

 its course gradually from west-northwest at the eastern extremity to 

 north-northwest at the western. (<?.) Its mean trend is northwest- 

 by-west (N. 56° W.), the mean trend of all the groups of the north- 

 westerly system in the ocean, (d.) The chain is a curving chain, 

 convex to the southward, and marks the position of a great central 

 elliptical basin of the Pacific having the same northwesterly trend. 

 The Hawaian is on the opposite side of it, slightly convex to the north. 



The Marquesan range lies in the same line with the Fanning group to the 

 northwest, just north of the equator; and, if a connection exists, another great 

 chain is indicated, — a Marquesan chain. 



(3.) Australasian chain. — New Hebrides and New Caledonia belong 

 to the Australasian island-chain. The line of New Hebrides is 

 continued northwestward in the Salomon group and New Ireland, 

 though bending a little more to the westward, and terminates in 

 Admiralty Land, near 145° E., where it becomes very nearly east- 

 and-west : the length of the range is about 2000 miles. Taking another 

 range in the chain, New Caledonia, the course is continued in the 

 Louisiade group ; then the north side of New Guinea, which con- 

 tinues bending gradually till it becomes east-and-west, near 135° E.: 

 and in the southeast, belonging to the same general line, there is the 

 foot of the New Zealand boot. The coral islands between New 

 Caledonia and Australia appear also to be other lines in the chain- 



From New Guinea the east-and-west course is taken up by Coram, 

 and again, more to the south, in the Java line of islands ; and from 

 Java the chain again begins to rise northward, becoming northwest 

 finally in Sumatra and Malacca. 



The several ranges make up one grand island-chain, with a 

 double curvature, the whole nearly 6000 miles long. The relation 

 of the parts in the system is shown in figure 28,. in which a line 

 stands for each group and indicates its course. 



The composite nature of the chain is here apparent ; as also the 

 curving course, in connection with a prevailing conformity to a 

 northwesterly trend. 



(4.) Blending of the Australasian and Polynesian island-chains. — The 

 two chains blend with one another in the region of the Carolines. 

 This large archipelago properly includes the Ealick and Eadack 

 groups. At theTarawan group, just south, the Polynesian chain 

 divides into two parts, — the Ralick and Radack ranges. But the 

 main body of the archipelago (see fig. 27 and the chart) trends off to 



