346 J. D. Dana on the Plan of Development 
But look further, and consider that the great lines of elevation 
on the Pacific side are parallel nearly to the islands of the ocean; 
that these islands are like a long train stretching off from Asia 
to the east-southeast; that New Hebrides, New Caledonia in the 
southwest, with the foot of the New Zealand boot and north- 
western Australia, conform to the general parallelism; and it wi ] 
then be comprehended that we have been considering not simply 
a continental system of progress, but one involving the whole 
globe. It appears also from the history of the coral islands of 
the Pacific, that while the Tertiary and Post-tertiary elevations 
were going. forward on the Pacific border of North America, 2 
slow and gradual subsidence was in progress over a parallel region 
across the middle of the ocean. ‘he axis line of the Pacific is 
not only the main trend of its lands, but is also nearly the course 
of the ie subsidence which is indicated by the history of the 
nds. 
coral isla: 
Ill. I have said that these two systems of forces—the south- 
east and southwest—continued to act through the Tertiary period, 
working out the continent, and bringing it nearly to its adult ex- 
tent. At the meeting of this Association at Providence I pointed 
out the fact that at the close of the Tertiary there was a change in 
the movement; that during the following period, the Post-tertiary, 
there were high-latitude oscillations ; aed I endeavored to show, 
that there was first an elevation of the continent over the nort 
for the first or glacial epoch; then a subsidence (as shown by the 
seashore deposits on Lake Champlain, and the highest terrace of 
es and rivers) during a second or Laurentian epoch; au 
finally; an elevation to its present height, for the third or Terrace 
epoch. ether the elevation for the Drift epoch, be admitted 
or not, all agree that the oscillation attending it was a northern 
Oy ge These several changes thus affected mainly the 
atitudes north of the middle of the temperate zone, or were but 
slightly felt to the south of this. Itis a remarkable fact that 
the coasts of the Arctic regions, which have now been rather 
widely ao have not presented any Jurassic, Cretaceous OF 
Tertiary deposits, and there is, therefore, no evidence of their 
ocean, are proofs of similar lateral action there, but from the southwest. Then the 
dominance of these two trends in the uplifts over the whole continent in its oldest 
and newest regions and rocks, are like the warp and woof of a fabric, determined 
by the organizing forces themselves of the structure 
* Amer. Jour. Sci. vol. xly, (1843) 131, and [2], iii, 396, (1847). 
Ine consequence of these facts and principles may be here alluded to.—If the 
position of the Atlantic and Pacific has determined the main directions of the or- 
forces time, and if, owing to the direction, as the facts show, 
vations having the same strike or trend have been formed in successive ge 2 
cal ages, it is evident that the elevation theory of mountains, sustained by Bie 0° 
: must be received with much hesitation. One dial-plate for the world, 
such as he has deduced mainly from European geology, is a splendid hypothesis ; 
but it may not mark time for America or the other continents, 
