[BAILEY-MATTHEW] NEW BRUNSWICK GEOLOGY 107 



éjecta, together with some schists and other clastic rocks. The first 

 of the two divisions, under the name of the Portland Group, was 

 referred to the Laurentian and the second or Coldbrook Group to the 

 Huronian. The ground for this reference was the evident parallelism 

 which the groups bore, both in their lithological characters and order 

 of succession, to the Laurentian and Huronian as established by 

 Logan and others in the region of the Great Lakes, while portions of 

 them at least were unconformably overlaid by fossiliferous Cambrian 

 strata. 



The above view of the age of these rocks remained undisputed 

 for over thirty years, but, about the year 1906, the late Dr. R. W. 

 Ells, as, the result of certain examinations made by him, stated, with 

 great positiveness, that the greater part, if not the whole, of the 

 lower group was intrusive and of late origin, while the crystalline 

 limestone and associated quartzites, forming the upper division, were 

 not a part of the Laurentian formation but probably Cambrian or 

 possibly even Devonian. 



To the view thus advanced by Dr. Ells, the writers of the present 

 paper and by whom the Archaean age of the rocks in question was 

 first asserted, cannot subscribe. No doubt the larger part of the 

 coarsely crystalline rocks of the lower division are of intrusive origin, 

 occurring in the form of more or less extensive batholiths, and to their 

 intrusion is due in great measure the highly crystalline character of 

 the associated rocks and even the development in some portions of the 

 latter of a quasi-gneissic character, while the same extrusion would also 

 indicate that they were of later age than the rocks which they invade; 

 but though such batholiths occur in connection with what are prob- 

 ably Huronian rocks to be presently noticed, they have nowhere 

 been observed to penetrate the overlying Cambrian and they (the 

 granites) are lithologically different from those which, at a very much 

 later date, penetrated the Silurian and Devonian. 



For the above reason the authors of this paper are still disposed 

 to adhere to their original belief that the crystalline rocks of St. John 

 and its vicinity are of Pre-Cambrian age and to be more particularly 

 correlated with the group (the Laurentian) to which, in the classi- 

 fication of the International Committee, that name is now restricted. 



We come now to consider the calcareous rocks of the upper 

 division which by the writers of this paper were also referred to the 

 Laurentian System. This reference too has been questioned by Dr. 

 Ells, mainly upon the ground that certain limestones in Charlotte 

 County which were also so referred, were found by him to carry 

 Silurian fossils, He even advanced the view that the highly altered 

 banded slates and quartzites which at St. John are associated with the 



