56 ROYAL SOCIETY OF CANADA 



suit primarily from outflows of this nature and era, though afterwards 

 greatly modified by the efEeets of erosion. 



Tn the case of the Silurian rocks of Charlotte county the effects of 

 faulting on the determination of topography are to. be seen in a series of 

 successive downthrows concentric with Passamaquoddy Bay whose ex- 

 istence as well as fonn may have been thus determined. 



Still another instance connected with Silurian rocks in which 

 vertical displacements have been of importance in determining modem 

 configuration, is to be found along the contact of the ISTorthern Highland 

 region and that of the Northern Plateau, the change of level, as seen 

 about Nictor Lake and elsewhere being singularly abrupt. Somewhat 

 similar relations are to be seen in the western part of Carleton county 

 about Oak Mountain, 



Devonian. — It is generally agreed among those who have studied the 

 geology of the Maritime Provinces that among the disturbances which 

 lia.ve at various times affected the latter, none have been so important in 

 the determination of modem reliefs as those which occurred about the 

 middle or during the latter part of the Devonian era. The period has 

 indeed sometimes been called that of the Devonian Revolution, and, as 

 such, compared with the Green Mountain or Appalachian revolution or 

 Uiat which, at the close of the Carboniferous era, resulted in the forma- 

 tion of the Appalachian Mts. This conclusion is strongly supported by 

 the fact that the strata of all systems up to and including the Devonian 

 are thrown into folds, their strata, with the exception of the highest beds, 

 metamorphosed and debituminized, and that they are invaded by intru- 

 sive granites, boulders derived from which abound in the upper De- 

 vonian and Carboniferous conglomerates while wanting or nearly so in 

 those of greater antiquity. These granites form the axes of both the 

 southern and northern highlands and as they now form or are connected 

 with the esistence of conspicuous hill ranges, while themselves of very 

 deep-seated origin, the original height of these ranges, prior to denuda- 

 tion, must have been very considerable. Indirectly, also, their elevation 

 must have given rise to the great central triangular basin later occupied 

 by the rocks of the Carboniferous system. 



Among less conspicuous foldings attributable to the middle of the 

 Devonian one is to be seen in the city of St. John, where not only are 

 the Cambrian rocks thrown into close synclinal form, but have been 

 overturned to the north by pressure from the south and east, while over- 

 lying Devonian rocks have been sheared and thrust up along a reversed 

 fault so as to be brought into a position of apparent conformity with 

 the rocks of the older series. 



