66 BAILEY ON GEOLOGY OP 



thiu brds of limestone. Through the latter, which are quite peculiar in having the tbiu 

 layers of which they are composed, not only separated l>y thin shaly partings, but 

 divided across the layers into numeroirs partly separated blocks, as though disjointed by 

 the pressure to which they have been subjected, this locality is easily connected with 

 another, in which a similar association of strata may be seen, viz., that of the Aroostook 

 River between Ashland and Presqn'isle. Here again, a scries of coarse conglomerates, 

 carrying fragments of serpentine and jasper, in addition to a variety of metamorphic and 

 igneous rocks, is succeeded by heavy beds of sandstone, somewhat dioritic and vesicular 

 in aspect, and these by slates holding limestone layers in eA^ery way similar to those of 

 the Siegas. In the sandstones, besides carbonized vegetable remains, are impressions of a 

 coral, resembling Favosites, a Bryozoon, probably a Callapora, Orthis, Strophomena rhomboi- 

 dalis, Ehynchonella, Spirifera (like S. radiata, Sow.), Atrypa reticulans, Liu., and Cornulites 

 (like C. flexuosus, Hall)— the whole indicating an horizon about that of the Niagara 

 formation. Similar conglomerates and sandstones are widely spread over northern Maine, 

 and in the reports upon that State have been regarded as Devonian, but there would now 

 seem to be but little doubt that they are the equivalents of the Burnt Point and Point aux 

 Trembles rocks of Temisoouata Lake, and, with the latter, hold a position which is quite 

 low in the Silurian system. In the same portions of Aroostook County, Maine, the higher 

 members of this system are again represented by limestones, and are remarkable for the 

 number and fine preservation of the organic relics which they hold, the well known 

 beds of Sc^uare Lake or Lake Sedgewick having yielded not less than forty-two species, 

 mostly new, while similar beds near Ashland are but little less prolific. 



Finally, on Beccaguimic River, in Carletou County, New Brunswick, and on the 

 extreme southern edge of the great Silurian tract of that Province, strata are again met 

 with, which, though highly disturbed, exhibit much the same aspect as those which have 

 been described, with similar relations and organic remains. 



It will now be of interest to institute a comparison between the succession of Silu- 

 rian rocks as thus made out in northern New Brunswick, Quebec and Maine, with the 

 succession of the regions nearer to the Bay of Fundy. ^ 



In so doing, one of the first facts to attract attention is the almost entire absence, in 

 southern New Brunswick, of the great belts of limestone which constitute so marked a 

 feature in the north, and more particularly in the Province of Quebec. Indeed no un- 

 doubted equivalents of these Lower Helderberg rocks are known to occur in the former, 

 though apparently met with, to a limited extent, in south-eastern Maine, as observed by 

 Prof. Shaler. On the other hand, between the lower members of the system in the two 

 cases a very striking parallelism may be drawn. Thus, taking the section afforded by 

 the Mascarene peninsula, in Passamaquoddy Bay, as typical of the southern coastal 

 region, the grey felspathic and siliceous slates, which constitute its first two divisions, 

 apparently find their counterpart in the great body of slates, often also highly siliceous, 

 which border Lake Temiscouata between Burnt Point and Point aux Trembles, already 

 described as holding a fauna low down in the Silurian system. With the conglomcr.ates 

 of Burnt Point, the latter a local accumulation, they may be regarded as the probabl 

 equivalents of the Oneida, Medina and Clinton Groups of New York, of Divisions II and 

 III of the Anticosti series, or of Groups B and B' of Arisaig in Nova Scotia. Division III 

 of southern New Brunswick consists of sandstones, of greenish iiud purplish colours and 



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