346 /. 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 will 

 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, a 

 slow and gradual subsidence was in progress over a parallel region 

 across the middle of the ocean. The axis line of the Pacific is 

 not only the main trend of its lands, but is also nearly the course 

 of the great subsidence which is indicated by the history of the 

 coral islands.* 



III. 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 ; and I endeavored to show, 

 that there was first an elevation of the continent over the north 

 for the first or glacial epoch ; then a subsidence (as shown by the 

 seashore deposits on Lake Champlain, and the highest terrace of 

 the lakes and rivers) during a second or Laurentian epoch ; and 

 finally, an elevation to its present height, for the third or Terrace 

 epoch. Whether the elevation for the Drift epoch be admitted 

 or not, all agree that the oscillation attending it was a northern 

 phenomenon. These several changes thus affected mainly the 

 latitudes north of the middle of the temperate zone, or were but 

 slightly felt to the south of this. It is a remarkable fact that 

 the coasts of the Arctic regions, which have now been rather 

 widely explored, have not presented any Jurassic, Cretaceous or 

 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. xlv, (1843) 131, and {2], iii, 396, (1847). 



One 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- 

 ganizing forces through all time, and if, owing to the direction, as the facts show, 

 elevations having the same strike or trend have been formed in successive geologi- 

 cal ages, it is evident that the elevation theory of mountains, sustained by Elie de 

 Beaumont, 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. 



