J. D. Dana on the Origin of Continents. 99 
tained by finding that the effects of fire are most apparent on the 
ocean side of the mountains, precisely as about the Appalachians, 
yet to a more remarkable extent.* Indeed, there are no remains 
of volcanoes, or their ejections, to the east of the summit; while 
to the west, the country of Oregon is in many parts buried beneath 
basaltic or other volcanic rocks, and several existing voleanic cones 
have been described. Still farther, we observe a second, a third, 
and even a fourth parallel range of heights from the summit 
of the mountains to the coast; and the third (the Cascade 
range) rivals the Rocky Mountains in the height of some of its 
wy peaks. Vast fissures were opened to the fires below, as 
action. + Here, then, are the natural effects of proximity to a 
region of contraction—the Pacific—in which the remains 0 ig- 
_e action every where abound. 
s been well established that the Appalachian folds or 
pleation were made since the coal period, for the coal beds 
nelosed in the folds;{ and the rising of the Rocky chain 
ee sth subsequent to that era. The effect of contraction in pro- 
ducing these elevations, was therefore comparatively little felt in 
the very earliest ages, when the surface of the depressed (or ig- 
neous) portion was itself somewhat yielding, but subsequen uently, 
When it had become stiffened to a considerable depth by saalinen 
appears hence to be a perfect eoneyectanae= ween meee 
and the causes adduced. 
ter; for the irruption is in general an effect of a very different 
action, as has been urged by a This ond be as true of 
' * The same is the general schinaatiee of the Andes. In an account of the geo! 
of Chile, M. I, Don Saget says, speaking of the Andes in abe fatitude of ee 
* En regardant A coté de l'Ouest, on voit un yer sement comple let 
terrain soulevé: des fuilles et déchirements, des e sepealantn pic 
tions t és etinterrompues. En portant a cann la vue du cote de pote est, on 
ait. des pentes douces, des bancs de rochers presque horizontaux et ee 
interrompos.” ave 
i Ss out announce que le principal mouvement ui — 
aasion es Andes te ac va du cété viel U Ouest, ee eR ap cote Seer et: 7, 
iments ha! marquent Je rivage actuel ie ‘TOcea ean grate le Cap ee Rlosin: 
av Mont s Rocheuses, continue a se soulever d'une maniere ogee et — 
reepti lee ve mugissement des bruits souterra ee a 3, Bad. lio, nytivly trembie- 
ments $9, Jerre sheet. — Annales des Mines, iv ser.,1 
anites ma have been the: Cath products ; but ie’ existing voleanic | moun- 
tains “hats bas on and trachytes r their surface rocks. 
+ Ww. Be 
522, 
H. D. Rogers, Acad Assoc. Amer. Geol. and Nat., 1840-1842, 
