Geology and Landscape Development | Fresh Water | Soils Plants | Animals | Scenic Quality | Cultural Environment Sites of Interest | Topics & Habitats

Geology and Landscape Development
The Till Plain lies on the southeastern side of Cape Breton, on the lower part of the tilted planation surface (see Figure 29). The bedrock is dominated by Precambrian Fourchu volcanics with large outcrops of Cambrian granite and metamorphic sediments of varied composition. The bedrock is highly eroded and is presumed to be almost flat under the glacial deposits. This is difficult to verify because the whole District is covered by a thick layer of glacial till, sands, and gravels, with the bedrock exposed only along the coast.

The bedrock is cut by many parallel, northeast-southwest faults along which vertical movement has taken place. Gabarus Bay is believed to be the product of downfaulting along another set of faults oriented northwest to southeast.

Surficial Deposits and Landscape Development
Glacial ice from the exposed Scotian Shelf flowed onshore and then northeast during the Wisconsin glacial period, depositing a thick mantle of sands and gravels across the entire area. The thickness is variable but commonly achieves 30 m, with 12 m representing an average depth. Drumlins are common. The glacial deposits have completely altered the original drainage pattern. The surface is now covered with irregular lakes and wandering streams.

Typical curving barrier beach Click to enlarge

Inland the terrain is low-lying and rolling, rising across a series of ridges to about 125 m in the northwest. A dominant landscape feature is the Mira River valley, which extends from Framboise Cove northwards to about Marion Bridge and then sweeps eastwards to exit at Mira Bay. Its preglacial flow, which may have been to the south, was redirected by small changes in elevation and blockage of the original exit by glacial deposits. The lower reaches of the river have been dammed by glacial gravels to form a long lake. At Mira Bay the river funnels through a very narrow valley, in places only 50 m wide, with steep banks 20 m high.

The coastline of the Till Plain is relatively even and dips gently into the sea. Gabarus Bay is the only stretch of coast where sea cliffs are found. Sediment supply along the coast is variable. North of Gabarus, rocky shorelines, boulders, and cobble beaches are most common; south of Gabarus, the coast is indented with protected bays. Sand and gravel beaches are numerous. Between Point Michaud and Fourchu Bay an extensive series of cobble barrier beaches enclose large barachois ponds (see Figure 29). These beaches may have originally formed offshore and moved landward as sea levels rose.

Fresh Water
The many small lakes and freshwater wetlands are associated with streams scattered throughout this District. The pH levels tend to be neutral, ranging between 6.5 and 7.5.

Soils
The soils in this District illustrate how a strong podzol development associated with the climate along the Atlantic coast can override the effects of different parent materials. The soils have developed from sandstones, quartzites, and shales. The most common soil series is Thom, a well-drained sandy loam podzol usually associated with cooler and wetter highland areas such as the Cobequids. A feature of Thom soils is the accumulation of organic matter on the surface and "B" horizon. Closer to the coast, the imperfectly to poorly drained Mira and Arichat associate soils are more common.

On the granites around Lower St. Esprit, Gibraltar and Aspotogan soils are found. Shulie sandy loams occur between Loch Lomond and the Mira River. These are similar to soils in Unit 532 to the north. To the east of the Mira River, well-drained Kirkhill soils occur; these have a shaly loam texture and are relatively deep and free of stone. Ortstein layers are common in this District, and large areas of peat have built up.

Plants
The main controlling factors in this District are the cool, wet soils, the marine exposures, widespread disturbance, and insect damage. Along the coast, White Spruce is common, but inland Balsam Fir grows much better and is the dominant species. Some shade-intolerant species with fewer shade-tolerant species are found on better-drained soils inland. Black Spruce and larch are common in wet depressions. Hemlock was once common but is now rare, presumably having been removed through selective logging by early settlers. Spruce Budworm is rampant here.

Large bogs are a prominent feature. Considerable quantities of Bakeapple are found in the bogs on Scatarie Island, exposed headlands, and other coastal bogs and barrens. Heath vegetation, particularly Crowberry, is found on exposed headlands.

Marshy brook pools and Potentilla, Point Michaud Click to enlarge

Sand-dune and tidal-marsh communities with some beds of Eelgrass are found along the coast. Limited warm-water influence in summer has permitted the penetration of some marine plant species from the Gulf of St. Lawrence, such as Serrated Wrack, but marine flora is restricted by the cold water and ice action.

Animals
Low snowfall provides good deer-wintering habitat in this District. Staging areas for migratory waterfowl and shorebirds are found along this coast between Fourchu Bay and Framboise Cove. The islands provide important breeding habitat for seabirds. Green Island has the most southerly nesting colony of Black-legged Kittiwakes and is the only one known in the Maritimes. Elsewhere breeding populations of gulls, cormorants, Black Guillemot, and Common Eider can be seen. Pelagic seabird concentrations occur off Louisbourg and are probably associated with an area of deepwater upwelling. Ptarmigan and Arctic Hare have been introduced on Scatarie Island.

The Louisbourg lowland is a cold-water coast with extensive sea ice, resulting in an impoverished marine fauna of an exposed boreal character. Harbour Seals are common; Grey Seals used to breed on the Basque Islands.

Typical freshwater fish species include White Perch, Banded Killifish, sticklebacks and Brook Trout. The Mira River supports a unique population of Lake Whitefish.

Scenic Quality
This District contains a variety of landscapes and coastal scenery, the only constant being low relief - the area is almost flat except for Gillis Mountain and the hills around Gabarus Bay. Coastal scenery varies from rocks to cliffs to beaches, with the most impressive views being in Gabarus

Trail from Lighthouse Point Click to enlarge

Bay. Inland, scenic ratings are typically low to medium, though lake sections of Mira River provide many delightful scenes from boats. Despite the presence of drumlins, there is very little settlement, except for a scattering of fishing villages and long lines of summer homes ("bungalows") along the Mira.

Cultural Environment
This is a rugged coastline, sparsely populated, with scattered fishing villages. The French were drawn to Louisbourg by its ideal harbour and strategic location on Cape Breton Island. Today the Fortress of Louisbourg National Historic Site is the largest historical reconstruction in North America and presents the fascinating story of the French fort. The first recorded coal mining in the province was undertaken here in 1720. Small farms originally settled by Acadians who planted apple and plum trees can be found along the Mira River. Salmon and trout fishing have a long history on the river, beginning with the Mi'kmaq. Mira shores have yielded harvests of sand and gravel, but this industry has declined. A small coal mine operated at Broughton. Fireclay, found on both sides of the river, was used as early as 1727 by the French to create bricks for the construction of Fort Louisbourg. The French brickyard was later operated by the British for many years. Large quantities of stones have been quarried from the cliffs along the Mira.

Sites of Special Interest

• Point Michaud (IBP Proposed Ecological Site 26) - beach and sand dune system showing succession from bare sand to White Spruce forest
• Scatarie Island - provincial wildlife management area with bogs and barrens
• Little Lorraine to Big Lorraine - barren, rocky headlands with interesting flora
• Gooseberry Cove - a hanging bog, nesting sites
• Baleine - arctic-alpine flora
• South Head - bog contains Grass-pink
• Louisbourg National Historic Park - bogs, barrens, and forest; Precambrian volcanic ash, vent deposits, and dykes
• Green Island - nesting site for Black-legged Kittiwakes
• Main-à-Dieu - exposed cobble beach
• Hilliards Lake, Winging Point Lake, Belfry Lake, Marcoche Lake - barachois ponds enclosed by barrier beaches
• Mira River - a rare outcrop of fossiliferous Cambrian sandstone and shale on the south side of Mira River on the road between Marion Bridge and Albert Bridge

Associated Topics T2.2 The Avalon and Meguma Zones T9.3 Biological Environment T10.9 Algae T11.12 Marine Mammals

Associated Habitats H3 Freshwater H2 Coastal H4.1 Bog H5.1 Barren H6.3 Mixed Forest (White Spruce, Fir-Maple, Birch Association Associated Offshore Regions 911 Atlantic 915 Sydney Bight