MAINE AND NEW BEUNSWICK. 67 



more or less aiuygdaloidal ; aud similarly, iu the uorth, the beds of Point aux Trembles, 

 ou Lake Temiscouata, with their supposed equiA^alents on Siegas EiA^er, New Brunswick, 

 and on the Aroostook, in Maine, occur in similar relations and present much the 

 same aspect, iuchrding in both instances the occu.Treuce of much comminuted vegetable 

 matter. Division IV of the Mascarene section, consists of red and green slates and sand- 

 stones, with diorites aud felsites, aud so, again, similar rocks are found in this position 

 at Cape G-aspé, Cape Chatte, Metapedia Lake, Himouski, and near the base of Mount Wis- 

 sick. The felsites and associated trappean rocks of Aroostook County, Maine, as well as 

 those of Restigouche County, New Brunswick, may possibly represent this and the suc- 

 ceeding division (V) ; but the facts at present known, rather favor the idea that the former 

 are Cambro-Siluriau. The absence of the higher members of the system in southern New 

 Brunswick may be accounted for vipon the supposition that the barrier of Laurentian 

 rocks, alluded to on a former page, as extending along the coast subsequently to the close 

 of the Archœan age, continued to exist in Silurian times, and that while, in the north, 

 the later half of the Silurian age was a period of subsidence, iu the south it was chiefly 

 one of elevation, excluding the access of pure sea-water, aud hence, of such forms as arc 

 dependent on its presence. 



Of other strata observed in northern Maine aud New Brunswick, it is more difScult 

 to speak with confidence, their stratigraphical relations not having been fully worked out, 

 and fossils being as yet wanting. Of these the most important consist of a mass of fine 

 grained slaty felsitic and siliceous rocks, associated with dioritic and amygdaloidal sand- 

 stones, quartz-porphyries and agglomerates, which appear to stretch in parallel belts 

 across a considerable portion of Aroostook County, and in places rise into prominent hills. 

 One of these belts is conspicuously exposed about Churchill, Umsaskis and Spider Lakes 

 on Allegash River, and apparently extends thence past the head- waters of the Aroostook, 

 forming the Aroostook Mountains, and eastward to the Valley of Fish River, separating 

 the Silurian basin of Square and Eagle Lakes from that of Ashland and Presqu'isle ; while 

 a second, as yet only seen at a few points, lies to the south of the latter, here including 

 the steep and conspicuous conical peak known as the Haystack. No fossils have yet 

 been observed in the slates of this group (referred to iu the Maine reports simply as trap- 

 pean rocks), and we are hence without definite proof of their age, but the nature of many 

 of the pebbles in the Silurian conglomerates would seem to indicate that the former was 

 the source from which these were to a large extent derived, while there are also points in 

 which conglomerates, apparently Silurian and similarly constituted, have been seen to 

 rest unconformably upon the siliceous and felsitic rocks. Ou the other hand, these latter, 

 in their fine-grained flinty texture and banded aspect, as well as in their dark purple to 

 black colours, recall the similar beds which, iu southern New Brunswick, mark the base of 

 the Silurian system. If really more ancient than the latter — as seems most likely, — their 

 true position is probably that of the Cambro-Siluriau formation, to some portions of which 

 they also bear much resemblance. The same remarks will also apply to a series of fine 

 grained micaceous and gneissic sandstones and slates, of dark purplish and lilac colovirs, 

 which accompany the beds above described on the Allegash River. These latter are 

 peculiar iu being filled with imperfectly developed crystals, apparently of staurolite, 

 and are quite similar to some of the beds referred to on a former page, as occurring 

 along the course of St. Croix River, both near St. Stephen, and again in the western 



