390 Origin of the Grand Outline Features of the Earth. 
whether curved or straight, consist of a series of subordinate 
parts ; these parts having often a different direction from the 
line of the range. 
hat the lines, even when curving, cross or meet any 
transverse lines very nearly or quite at aright angle, the one 
dependent on the other or varying with it. Consequently— 
E. That the same grand chain may vary even sixty degrees 
or more in its course, and hence the trend of a ridge is no inde- 
pendent evidence of its age. Thus a northwest course may 
gradually change to an east and west, as in the great Java range 
from New Hebrides to Java, and thence become northwest again, 
i matra:—a west-northwest range may change to north- 
northwest, as in the great Pacific chain from the Society Islands 
to the northernmost of the Marshall group. A north-northeast 
range may change through northeast, to east and west ; and also 
a north and south range may go through the same changes, as 
shown along the east coast of Asia and elsewhere.* *Just west 
of New Guinea the east and west line is a little north of east in 
Timor. Consequently, while northeast and northwest lines are 
on the whole most common, there are other courses to be consid- 
ered, and all are so dependent that they evidently must have a 
common explanation. 
Causes of the Earth's Features. 
The direction of mountain chains is universally attributed . 
the courses of former fissures in the earth’s surface ; and as islan 
come under the same head, and coast lines are mostly dependent on 
the ranges of heights adjoining, the question before us is reduc 
to this :—What can have occasioned such ranges of fissures, with 
their several peculiarities ; their composite character, general uni- 
formity of direction, curves, irregularities, and usual rectangular 
intersections ? ‘ 
Peculiarities of Fissures.—Before proceeding farther, it is 1m- 
portant to understand the general character of fissures; and we 
present a case to the point from the map accompanying the elab- 
_* The same principle is recognized by the Professors Rogers, in view of the facts 
observed by themin the Appalachians. “rans. Assoc. Amer. Geol., 1840-42, p. 540. 
t Report, &c., by James G. Percival, 495 pp. 8vo., New Haven, 1842. 
