Swanage Bay from Ballard Down is part of a discordant coastline

A discordant coastline occurs where bands of differing rock type run perpendicular to the coast. Swanage is a small coastal Town in the south east of Dorset, England. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere In Geometry, two lines or planes (or a line and a plane are considered perpendicular (or orthogonal) to each other if they form congruent The coast is defined as the part of the land adjoining or near the Ocean.

The differing resistance to erosion leads to the formation of headlands and bays. Headlands and bays are two related features of the coastal environment A hard rock type such as granite is resistant to erosion and creates a promontory whilst a softer rock type such as the clays of Bagshot Beds is easily eroded creating a bay. Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. A promontory is a prominent mass of land which overlooks lower lying land or a body of water (when it may be called a Peninsula or headland) Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and In Geology, the Bagshot Beds are a series of Sands and Clays of shallow-water origin some being fresh-water some marine

Part of the Dorset coastline running north from the Portland limestone of Durlston Head is a clear example of a discordant coastline. Dorset ( (or archaically, Dorsetshire) is a county in South West England on the English Channel coast Portland stone is a Limestone from the Jurassic period quarried on the Isle of Portland, Dorset. The Portland limestone is resistant to erosion; then to the north there is a bay at Swanage where the rock type is a softer greensand. Portland stone is a Limestone from the Jurassic period quarried on the Isle of Portland, Dorset. Swanage is a small coastal Town in the south east of Dorset, England. Greensand is an olive-green coloured Sandstone rock which is commonly found in narrow bands particularly associated with bands of Chalk and North of Swanage, the chalk outcrop creates the headland which includes Old Harry Rocks. Swanage is a small coastal Town in the south east of Dorset, England. Chalk (ʧɔːk is a soft white porous Sedimentary rock, a form of Limestone composed of the Mineral Calcite. Old Harry Rocks are Chalk stacks located directly east of Studland and to the north of Swanage in Dorset.

The converse of a discordant coastline is a concordant coastline. concordant coastline occurs where the bands of differing rock types run parallel to the Coast.

Examples

• The coastline around Swanage (50°36′24″N 1°57′54″W / 50.60667, -1.965) is an example of a discordant coastline. Swanage is a small coastal Town in the south east of Dorset, England.