1865.] GEOLOGY OP NEW BRUNSWICK. 315 



Laurentian series of Canada. It is with much gratification that 

 we are now enabled to confirm, with a good degree of certainty, 

 this opinion of their antiquity and geological position. 



" The facts upon which this decision is based are chiefly these : 

 first, the great metamorphism of the series, and secondly, the posi- 

 tion which it holds with reference to the overlying formations. It 

 will be impossible clearly to explain the latter without anticipating 

 the description of the groups which are to follow, but it will be suf- 

 ficient here to say that one of these groups, that of Saint John, 

 formerly supposed to be connected with the Devonian series, has 

 been shown, upon the evidence, of its fossils to be undoubtedly 

 Primordial, or to be the equivalent of the Potsdam rocks of other 

 portions of North America — rocks at the very base of the Lower 

 Silurian series. Were the rocks of Portland simply underneath 

 the fossil-bearing beds of the Saint John group, we should still be 

 obliged to regard them as Azoic ; but, as will hereafter be shown, 

 they are really separated from the latter by the entire mass of the 

 Coldbrook group, representing certainly not less than 7000 feet of 

 stratified deposits, which must have been formed in the interval 

 between the laying down of the Portland beds, and the shales and 

 sandstones of Saint John. 



" If then, as is probable, the Coldbrook group is the partial 

 representative of the Huronianbeds of Canada, we cannot hesitate 

 in assigning the subjacent syenites and limestones of Portland to 

 the great and still more ancient Laurentian series, a group hereto- 

 fore supposed to be unrepresented in this portion of the continent. 

 " In corroboration of this view, we have only to call attention to 

 the great similarity of the two formations in their mineral compo- 

 sition, and their extreme metamorphism. Without entering into 

 minute details, (for the study of which the reader is referred to the 

 Reports of Sir William Logan on the Geology of Canada,) it may 

 be sufficient here to say that this resemblance is apparent in the 

 succession of stratified deposits, consisting in both, principally of 

 gneiss, quartzite, limestone, anorthosite (?) and occasional bands of 

 mica-schist, together with syenite, and rocks which can with 

 difficulty be distinguished from intrusive granites. Both hold 

 beds of graphite, sulphurets of the different metals, serpentine (in 

 connection with the calcareous beds, producing ophiolites), as well 

 as many simple minerals, such as hornblende, muscovite, pyral- 

 lolite (?) tourmaline, feldspar, and others. The abundance of mag- 

 nesian silicates in the Portland rocks is also remarkable, as observed 

 by Mr. Matthew, and suggests the possibility that the limestone 



