264 STRATIGRAPHICAL GEOLOGY. 



Mt. Washington, it may be tliat this elevation would hardly effect much 

 alteration in the andalusite strata, or no more than is evidenced by the 

 smaller curves along the carriage-road. But the amount of disturbance 

 upon the Hcldcrberg rocks themselves, in the edge of the mountains, 

 was enormous. 



The attempt to localize in time these several disturbances is quite un- 

 satisfactory, as our data for generalization are so meagre. These sugges- 

 tions may be regarded as merely inviting the attention of scientists to 

 the problem. Some would doubtless prefer to refer one of these epochs 

 to the Appalachian revolution, at the close of the Carboniferous, or to an 

 earlier one at the beginning of the same era. I have thought these latter 

 disturbances inapplicable to the mountains, since none of the upper De- 

 vonian or Carboniferous beds occur within a hundred and fifty or two 

 hundred miles of them ; and their foundations had probably become well 

 fixed before these dates, so that they were not sensibly affected by either 

 of the Carboniferous convulsions. 



EozoiG, OR Paleozoic? 



The proper place for presenting arguments in favor of the Eozoic or 

 the Paleozoic age of the White Mountain rocks will be at the end of the 

 subject of Stratigraphical Geology; but our present expression of opinion 

 would not be complete without a brief statement of the principal argu- 

 ments upon both sides of the question, whether the bulk of the White 

 Mountains belongs to the Eozoic or the Paleozoic system. 



As seen by the review of opinions, the first theorists accepted the view 

 that these rocks were Primary or Eozoic. Subsequently it became fash- 

 ionable to call them all altered or metamorphic Devonian or Silurian, for 

 these reasons: — i. There is a marked lithological difference between the 

 Adirondack and White Mountain gneisses. 2. The north-easterly unal- 

 tered continuation of the formations consists of Devonian and Silurian 

 groups; — therefore the White Mountain rocks are the same in a meta- 

 morphic condition. 3. In proceeding south-easterly from the St. Law- 

 rence and the Adirondacks, the strata dip easterly most of the way to 

 the sea-shore. Therefore we rise in the geological scale after leaving 

 the Laurentian; and hence the White Mountain rocks must be Devo- 

 nian, as they follow the Silurian of the Champlain valley. 4. A section 

 from Labrador across the peninsula of Gaspc to Nova Scotia carries us 



