North Mountain, Cobequids, Cape Breton Plateau, uplands in New Brunswick

It has been shown that the land surface of the Maritime Provinces is readily divisible into systems of uplands and lowlands; moreover, on looking at the maps, we see that the grain of the country, that is, the direction of the rock strikes, is mostly in a N. E.S. W. direction. The long axes of the basins or synclines, already mentioned, are similarly oriented. Examination of a physiographic map of North America, shows that a similar condition prevails over the whole eastern margin of the continent. The Maritime Provinces form part of the folded Appalachian Mountain region which has undergone modification during several mountain building epochs. Faulting as well as folding has had important effects. The scarps bordering the Cobequid Mountains, the Pictou-Antigonish Uplands and the Cape Breton Plateau indicate some of the important fault lines.

The present surface, however, does not bear a great deal of resemblance to the old folds, it truncates or cuts straight across them all. How was it developed? Why do we see such long level skylines on the North Mountain, the Cobequids, the Cape Breton Plateau, or the various uplands in New Brunswick?

Starting at sea level on the south shore of Nova Scotia it rises steadily to the crest of the South Mountain (600 feet A. T.). Across the Annapolis Valley the North Mountain reaches 700 feet A. T.; the Advocate Mountains are between 800 and 900 feet high. The Southern Uplands of New Brunswick are about, 1,200 feet A.T. Further north and fully 200 miles from the Atlantic we encounter a skyline slightly above 2,000 feet A.T. in the Central Highlands. In other words, the general elevation of the uplands increases at the rate of about 10 feet per mile. A similar section may be drawn from south to north on Cape Breton Island.

Old Erosion Surfaces

The logical explanation is that these uplands are the remnants of an old erosion surface preserved on the harder rocks. The mountains, mentioned in a previous paragraph, were, over a long period of time, completely eroded by rain and rivers and reduced almost to sea level. This condition was very widespread, pieces of this erosion surface or peneplain (almost a plain) being found all the way from Georgia to Northern Labrador. This immense lowland did not, however, remain at or near sealevel. A new cycle of mountain building was initiated and the peneplain was raised and warped. The rivers on its surface took on a new lease of life and began to cut down their valleys, erosion being most effective on the belts of weaker rocks. It would seem that a second base-level was also established, since the great plateau of northwestern New Brunswick is about 1,000 feet below the skyline of the Central Highlands. It too was raised and a third cycle of erosion has carved out the present lowlands while still more recent tilting has allowed the sea to advance over large areas that were once dry land.


The last major event in the shaping of the surface features of the Maritime Provinces, as in most of Canada was the Ice Age of the Pleistocene period. Great ice sheets spread over the land, and, when they melted, a great mixture of unconsolidated material was left upon the bed rock.

The wooded nature of the Maritime landscape has prevented complete systematic mapping of the glacial features but they are known to include moraines, drumlins, kames and eskers similar to those described in detail for other parts of Canada. In particular it is worth noting that there are many hundreds of drumlins in Nova Scotia. Halifax, Chester, Mahone Bay, Guysborough County and the interior of Queen's county all have these oval hills of drift in abundance.

Glaciation has completely disarranged most of the previously established drainage patterns causing the country to be dotted with swamps and lakes. Rivers, forced to carve new courses, have many interruptions in the form of rapids and waterfalls. Both the Reversing Falls and Grand Falls on the St. John River are of this type.

No comments: