The principal soil types in the region include a narrow coral reef along the coast bordered inland by a narrow strip of coastal sands towards the north where it is permeated by narrow bands of grumosolis brown clay soils. The soil south of Lamu is composed of by-alternate bands of loams beyond which the grumosolis are permeated by thick bands of ash and pumice soils. The shoreline has an extensive fossil reef which is raised a few meters above present sea-level. The coastline consists of a series of sandy beaches interrupted by rocky outcrops. There are extensive fringing reefs all along the coast.
Sandy beaches are extensive along the western coast, while fluvial deposits cover the eastern coast.
The north-west and parts of the west coast contain the most extensive mangrove forests in the entire region. The north-east is a mountainous region with little habitable area near the coast, a rugged indented coastline is characteristic of this region. There is an extensive barrier reef formation, some 24 km in length, off the south-east coast of Toliasa. The east coast also has extensive fringing reefs and coral sand barrier beaches behind which run a chain of lagoons connected to form an inland waterway called the Pangalanes canal. Mauritius Mauritius, a member of the Mascarene group of islands has a mountainous topography contained within a coastline of 200 km and a total area of 1,865 km 2 .