Unit 585 is divided into two sub-Units:
(a) Grand Narrows
(b) Sydney River

Geology and Landscape Development
In Cape Breton, Horton strata are not found east of the Great Bras d'Or Channel. In eastern Cape Breton the earliest Carboniferous deposits are represented by the Grantmire Formation. These strata

Nova Scotia Highland Village, Iona Click to enlarge

are probably the same age as the Horton Group but are made up of coarser materials: conglomerates, grit, and coarse sandstone. The Iona Uplands are predominantly underlain by Grantmire strata deposited as alluvial fans directly onto the ancient granites and schists of the Boisdale Hills when they stood on the side of the intermontane basin (see Figure 20).

The Iona Uplands Unit is divided into Grand Narrows (sub-Unit 585a) and Sydney River (sub-Unit 585b). In both areas the Grantmire rocks form resistant shoulders on the upland block of the Boisdale Hills and give steep slopes rising directly from the Bras d'Or lowland. The elevations reach a maximum of 200 m, in keeping with the location of this area on the tilted planation surface.

Grand Narrows (sub-Unit 585a)
This area includes a section of upland between St. Patricks Channel and the Great Bras d'Or made up of Horton and Grantmire strata. This upland is extensively crosscut by faults and stands as a hill with a fault scarp on the east and a more gradual descent to the Submerged (Bras d'Or) Lowland on the west.

Sydney River (sub-Unit 585b)
This area is mantled by thick glacial deposits, kames, eskers, and outwash gravels which partly fill the river valley and create a series of shallow lakes connected by narrow channels. These deposits are evidence of an ancient lobe of ice in East Bay which extended from the Submerged Lowland during the late stages of the Wisconsinan glaciation. As the ice melted, streams carried outwash material towards the Cabot Strait.

Fresh Water
There is very little surface-water coverage in sub-Unit 585a. In sub-Unit 585b, several isolated brooks drain into Sydney Harbour, and a few lakes are found in the northern portions. The water is alkaline, with pH levels averaging 7.5.

Soils

Grand Narrows (sub-Unit 585a)
In this area, soils are mostly well-drained Westbrook sandy loams developed from conglomerates, with imperfectly drained Millbrook clay loams. Small areas of Woodbourne silt loams also occur.

Sydney River (sub-Unit 585b)
Westbrook soils are dominant, with areas of imperfectly drained Debert silt loam (often with a cemented layer). Queens soils, a clay loam, are found at Point Edward. Some areas of coarse Hebert soils occur on outwash sands and gravels.

Plants
(See District 560, Submerged Lowland.)

Cultural Environment
The Sydney coal mines provide the foundation of much of the industrial base in the Sydney River area (sub-Unit 585b). In certain areas of the Iona Uplands, small farming occurs.

Sites of Special Interest

• Blacketts Lake to Sydney River - kames, eskers, and outwash gravels along the river valley; rare aquatic fauna
• Nova Scotia Highland Village Museum, Iona - Scottish heritage of Cape Breton

Provincial Parks and Park Reserves

• Barra Forest
• Iona

Proposed Parks and Protected Areas System includes Natural Landscape 48.

Scenic Viewpoints

• Unit 585a: Barra Strait (Iona-Grand Narrows)

Associated Topics T2.4 The Carboniferous Basin T3.1 Development of the Ancient Landscape T3.4 Terrestrial Glacial Deposits and Landscape Features T9.1 Soil-forming Factors T11.16 Land and Freshwater Invertebrates T12.3 Geology and Resources

Associated Habitats See District 560, Submerged Lowland) Associated Offshore Units 915 Sydney Bight 916 Bras d'Or Lake