4 
On the Geological Age of the White Mountains. 411 
slate and granite. But it involves we conceive two errors, first, 
that of assigning to all the strata of the gneissoid class, merely 
in virtue of their crystalline aspect, a date remoter than that of 
the protozoic or earliest fossiliferous deposits; and secondly, the 
errorof supposing that the strata of these mountains contain no 
organic. remains. So long as their fossiliferous character was 
undiscovered, the metamorphic condition of these rocks might 
naturally enough deceive the observer and lead him to false 
inferences in relation to their age. 
Having in the month of July-last, enjoyed the opportunity of 
studying with some care the structure and composition of that 
part of the chain which is exposed to view in the picturesque 
and deep defile of the Saco, we had the good fortune to detect 
in the vicinity of the Notch, the fossiliferous character of a por- 
tion of the strata, and to see through the metamorphic disguises 
in which intense igneous action has obseured these originally 
sedimentary paleozoic masses. We succeeded in determining 
some of the organic remains sufficiently to identify thereby some 
of the formations, much altered as they are from the purely sedi- 
mentary aspect, and from these data we have attempted to deduce 
some inferences respecting the limit of antiquity of these moun- 
tains, and the date of their elevation. By detecting in many 
of the pseudo-granitic rocks a genuine sedimentary stratification, 
we were able to follow in sundry places the true direction of the 
almost obliterated bedding, and to discover the course of the 
anticlinal axes. ‘These once clearly recognized, led us finally to 
conclusions which have much interested us in regard to the 
