22. 



6oo to 1,000 feet (180 to 300 m.) in altitude. The ac- 

 cordance of the summits of these hills, although not perfect, 

 is so close, particularly in view of the mountain structures 

 which are truncated by the gently undulating surface, that 

 the plateau can be regarded as an ancient plain of subaerial 

 denudation, similar to and contemporaneous with the up- 

 land of southern New Brunswick and the peneplain of 

 southern New England. The surface of the upland slopes 

 gently and steadily seaward, from northwest to southeast, 

 as a result of the regional uplift which it has suffered since 

 the period of base levelling. 



The upland also presents the appearance of having been 

 carved intaglio. Sunk beneath its surface are valleys too 

 numerous to count. In the higher northern part of the 

 peninsula, — for example, around Arisaig and Antigo- 

 nish, — the valleys are deep and gorge-like. Farther south, 

 where the plateau is lower, the valleys are shallower and 

 are somewhat obscured by a filling of glacial drift. Here 

 as in other parts of the Appalachian province, the dissection 

 of the upwarped Cretaceous peneplain has been deep and 

 sharp in the elevated interior and shallower and wider 

 near the coast. 



The Cobequid mountains, crossed by the Intercolonial 

 railway about midway between Amherst and Truro, 

 may be regarded as a connecting link between the upland 

 of Nova Scotia and the upland of southern New Bruns- 

 wick. Here, on an outlying mass of hard crystalline rocks, 

 the surface of the Cretaceous peneplain has been preserved 

 while the intervening sediments have been reduced to 

 lower levels. 



Cumberland and Colchester lowlands. — The areas occupied 

 by the comparatively weak sediments of Carboniferous, 

 Permian and Triassic age, more especially over the isthmus 

 that ties Nova Scotia to New Brunswick around the head 

 of the Bay of Fundy, are lowlands, half drowned by the sea. 

 Following the uplift of the Cretaceous peneplain, denuda- 

 tion by the rejuvenated rivers, proceeding with far greater 

 rapidity in these areas of non-resistant rocks, developed 

 a secondary peneplain while the areas of harder structure 

 both east and west were left standing as deeply dissected 

 plateau masses. This lower, later peneplain of the Tertiary 

 period extends northwestward along the shore of the gulf, 

 over eastern New Brunswick and Prince Edward Island. 

 Like the older peneplain, this lowland of the Tertiary 



