MAINE AND NEW ERUNSWICK. 63 



cousiderable part of it, or whether, ou the other hand, the fossil-bearing bauds are not 

 rather to be regarded as portions of newer formations enfolded among strata really of 

 much greater antiqiiity. The resolution of this question, upon which some further facts 

 will presently be stated, is one of the most important problems still demanding the 

 attention of those interested in New Brunswick geology. 



It is necessary now to refer more particularly to the grounds upon which the rocks 

 skirting the northern side of the northern granite axis are, in part at least, held to be of 

 Cambro-Silurian origin. Of these evidences the first, that of unconformability to the Silu- 

 rian, may be seen anywhere along the line of contact between the two formations, and is 

 eA'idenced alike by discordance of dip, by transverse progressive overlap, and by the com- 

 position of the conglomerates of the newer series. Within a few miles of the border are 

 beds of coarse and highly calcareous conglomerates, conforming to the Silurian succession, 

 and filled with pebbles derived from the Cambro-Silurian rocks near by, and across which 

 their trends would carry them. The evidence of fossils is at present confined, so far as 

 the western portion of New Brunswick is concerned, to the occurrence, first observed by 

 Matthew, of linguloid shells in black calcareous and siliceous beds upon the Beccaguimic 

 River in Caileton Countj', and which have since been found to be associated with trilo- 

 bites of the genera Harpes, Trinudetis and others, indicating an horizon which is certainly 

 Ordovician ; while in the north-east of the Province, in what are believed to be rocks of 

 the same group, remains of graptolites, apparently Lower Silurian, were observed by Mr. 

 Ells. To these facts it may be added that in the occurrence of bright green and red slates, 

 such as occur near Woodstock and Newburgh, New Brunswick, and the association with 

 these latter of heavy beds of coarse grey grit, similar to those of the Sillery formation, a 

 general resemblance is sixggested to the rocks of the so-called Quebec Group, as seen along 

 the Temiscouata Portage Road, and the south shore of the St. Lawrence. It is not impro- 

 bable that the slates of Waterville, Maine, containing the so-called Nereites, etc., may be 

 a part of the same great belt. 



It has been usual to regard the granites upon which the slates last described repose 

 as being of Devonian age, chiefly upon the ground of their evident resemblance to the 

 granites of southern New Brunswick, and the fact that pebbles, apparently derived from 

 the latter, are abundant in the Lower Carboniferous conglomerates, while they are rare 

 in those of earlier formations. In neither district, however, are the granites known to 

 actually invade undoubted Devonian sediments, whereas such invasion in the case 

 both of the Cambro-Silurian and Silurian, has been frequently observed. The Silurian 

 conglomerates of the north also include both granitic and syenitic pebbles. 



The line of contact of the Lower and Upper Silurian, referred to above, crosses the 

 international boixndary not far from the Monument at the extreme source of St. Croix 

 Eiver. From this jîoint northward in New Brunswick, the admirable section afforded 

 by the valley of St. John River, running x-)arallel with and for a considerable distance 

 actually forming the boundary, has, with a single exception (that of a narrow belt of 

 Carboniferous and possibly in part DcA'onian sediments, a few miles north of Woodstock), 

 failed to show the existence of any rocks other than those of the Silurian system. At the 

 same time it was here, as elsewhere, found very difficult, owing partly to the comparative 

 uniformity of the beds, partly to the general and excessive plication to which they have 

 been subjected, and partly to the pavicity of fossils, to determine with any degree of 



