ESSEX COUNTY. 223 



truth of this question, the character of the rock does not seem to be of any importance : for 

 augiu we know, tliis species of rock may enter into the formation of mountains of all ages, as 

 well as any primary mass. This conclusion, however, is the one to which I have arrived, 

 independent of the direction of its range, viz. that it is newer than the mountains of New- 

 England. I have the Hoosic and Green mountain ranges in view in this comparison. It is 

 true that the latter has suffered a movement since the deposition of the new rcdsandstonc ; 

 still, when the mountains of New-York arc taken in connection with the tertiary of Lake 

 Chaniplain, we must regard the latest movements of elevation to have occurred at a very 

 modern period. But to determine when those movements commenced, is a difficult matter. 

 We know that the Hudson river scries is disturbed along the eastern base, or northeastern 

 termination of some of those ranges ; an event which may have happened very soon after their 

 deposition, or at a still later period. More than one mountain range may have been elevated 

 in the same era. Admitting that these elevatory movements are paroxysmal in a given direc- 

 tion, it is very possible that during a period of quiescence, or between two paroxysms, an 

 elevatory movement may occur in another direction, and alternate states of movement and 

 repose may be the true condition of a continent. It may turn out, however, that the forces 

 may be more active, or remain longer quiescent, in one system than in another. I conceive, 

 from all the facts which bear upon this subject, that however certain it may be found that 

 elevatory movements may have taken place since the deposition of a certain mass which is 

 disturbed, still we shall not be able to show, even relatively, when the earliest movements 

 were imparted ; for an upward movement may be slight, and not affect the masses of sediment 

 accumulating around or at the base of a chain ; it may take a much longer period to achieve 

 a given elevation ; and during repose, or the moderate action of the forces, a range in another 

 direction may be formed. But however this may be, there appears to be one point established, 

 namely, that the forces which uplift mountain ranges act in certain directions in preference 

 to others. 



To return for a moment to the shape of the mountains of hypersthene rock : I found them, 

 as has been remarked, with conical summits ; each main summit presents generally three 

 peaks, the highest of which is nearly central, or there is found a shouldered mountain. This 

 form is so extremely rare in the Hoosic range, that I do not remember to have seen a good 

 example of it, yet it is the principal form where the hypersthene rock composes the mountain. 

 In these remarks, I may be in error in attributing the form or contour of the mountain to 

 the kind of rock of which it is composed ; but I believe that none but an vmstratified rock can 

 produce precisely such forms as we find in the Adirondack gi-oup ; and I attach some impor- 

 tance to the remarks, from the application we may sometimes make of them in forming our 

 opinion of a mountain in the distance, whether a stratified rock forms its summit or not. Cer- 

 tainly none of the mountains of gneiss, and they surround the Adirondacks on all sides, ever 

 assume the form which these uniformly present ; and I believe it may be told at a distance, 

 whether a given- mountain is composed of gneiss or hypersthene, by the shape of its summit. 



There is one feature in which the Adirondacks differ from the White mountains : it consists 

 in the amount of boulders which cover the sides of the latter ; for from what I learn from 



