MARITIME APPALACHIANS 



191 



New Brunswick and Prince Edward Island 



New Brunswick falls naturally into four major topographic divisions whose 

 boundaries, however, in most places are not sharply defined. The first, which 

 may be regarded as the main axis of the province, is known as the Central High- 

 lands, an upland region developed largely on resistant granitic, volcanic, and 

 metamorphic rocks. It trends northeast through the central part of the province 

 and is made up of ridges and hills, most of which have flat summits. Its eleva- 

 vation varies considerably, but much of it has an average height of about 1,000 

 feet. The highest part is where the tributaries of Miramichi, Nipisiguit, and 

 Tobique Rivers take their rise. Here broad summits have a general elevation of 

 about 2,200 feet, with some ridges and peaks rising to still greater heights. For 

 example, Mount Carleton, the highest point in the province, has an elevation of 

 2,690 feet. 



To the northwest of the Central Highlands is a second division, which may 

 be termed the Northern Upland. It stands at an elevation of 800 to 1,000 feet 

 above sea level and is developed on folded Paleozoic strata. The upland pre- 

 sents a remarkably uniform, flat-topped surface whose regularity is broken only 

 by a few peaks and ridges rising slighdy above the general level and by valleys 

 such as those of the St. John and the Restigouche, which are deeply entrenched 

 in it. The Stewart highway from Campbellton to St. Leonard crosses this belt. 

 The third division, the Eastern Plain, lies to the east of the Central High- 

 lands, and makes up almost one-half of the province. It is a region of low relief, 

 rarely more than 600 feet high, sloping gendy to the Gulf of St. Lawrence. Its 

 underlying rocks are mosdy flat or gendy dipping Carboniferous sediments. 

 Prince Edward Island may be regarded as an outlier of this division, and the 

 Cumberland-Pictou lowland area of Nova Scotia is continuous with it. 



The fourth division, termed the Southern Highlands, lies along the Bay of 

 Fundy. It is mainly an upland belt of ridges of which the most important is the 

 II flat-topped Caledonis Mountain belt of Albert, Kings, and St. John counties, 

 'J which reaches a maximum elevation of 1,350 feet southeast of Markhamville. 

 j To the southwest, in Charlotte county, the belt merges into the Central High- 

 I lands. The region shows considerable topographic diversity and a great variety 

 of rock types. The ridges are composed mainly of hard volcanic and intrusive 

 , rocks, whereas minor lowland areas within the belt have been carved from 

 - weaker strata. 



i Quebec 



In Quebec the Appalachian region is bordered on the northwest by the St. 

 ji Lawrence Lowlands into which it merges imperceptibly. In fact, considered 

 | from the point of view of topography, the lowland belt overlaps the Appalachian 

 geological region. To the southwest the upland region includes three parallel 

 groups of ridges and isolated hills and mountains. These are highest in the south, 

 and decrease in elevation towards the northeast. The highest point is Round 

 Top on Sutton Mountain, elevation 3,175 feet, near the Vermont border. 



The most easterly of the three belts is known as the Megantic anticline. It 

 forms part of the International Boundary, and to the northeast passes into 

 Maine. To the west the Stoke Mountain anticline extends as far as Lake St. 

 Francis, where it loses its identity. Still farther west, a little beyond Lake Mem- 

 phremagog, the third range, the Sutton Mountain anticline, is a continuation 

 of the Green Mountains of Vermont. Between the anticlinal ranges the country 

 varies from 900 to 1,000 feet in elevation, presenting in places a remarkably 

 level surface. To the northeast, it continues as an upland belt of ridges and roll- 

 ing country cut across by deep valleys such as those of the St. Francis and 

 Chaudiere. It decreases in elevation to a point about opposite Quebec City, but 

 farther northeast it rises again and in the central part of the Gaspe Peninsula 

 becomes the Shickshock Mountains, with elevations ranging up to more than 

 4,200 feet. The individual members of this range show broad flat summits and 

 the range is bordered both to the north and south by another flat-topped upland 

 at a lower level into which the present river valleys are deeply incised. On the 

 north side of the Shickshock the descent to the lower upland is for the most part 

 abrupt; on the south it is more gradual. The lower surface slopes off both to the 

 north and to the south, and to the southwest merges with the Northern Upland 

 of New Brunswick. 



STRATIGRAPHY 



Introduction 



The Maritime Appalachians are a continuation of the New England 

 Appalachians and present much the same geology. See geologic map of 

 Fig. 12.2. They are composed mostly of Paleozoic rocks, both sedimentary 

 and igneous, but some older Precambrian and some younger Triassic 

 rocks are also present. The chart of Fig. 12.3 correlates the principal for- 

 mations of Nova Scotia, New Brunswick, and Quebec, and may be re- 

 ferred to in the following brief enumeration of the stratigraphic systems. 

 Several groups such as the Green Head, the George River, and the Cold- 

 brook are known definitely to be Precambrian, and others such as the 

 Meguma and Macquereau are regarded as Precambrian but on less satis- 

 factory evidence. They may be Cambrian. Certain granite intrusions of 

 the southern highlands of New Brunswick and in Cape Breton Island are 

 also probably Precambrian, but absolute proof of this has not been estab- 

 lished. Other belts of rock shown on early maps as Precambrian arc now 

 either definitely known or else inferred to be of Paleozoic age ( Alcock, 

 1947). 



