(ii) The West Coastal Plain

It lies between the Sahyadris and the Arabian Sea. It is about 1400 km long and 10 to 80 km wide. It has an elevation up to 150 m above sea level, reaching more than 300 m at places. The Western Coastal Plain is characterised mainly by sandy beaches, coastal sand-dunes, mud-flats, lagoons, alluvial tracts along rivers, estuary, laterite-platforms and residual hills. The Sahaydris (elevation 750-1225 m) run parallel to the plain and present their steep face to the low lands with Thalghaat and Bhorghat (gaps) in the north and the Palghat (Plakkad Gap) in the south of Nilgiri. The northern part of the west coastal plain, known as the Konkan Plain, is about 530 km long and 30 to 50 km wide. Southward is the Karnataka coastal plain which is about 525 km long and 8 to 25 km wide. It is the narrowest part of the West coastal plain. The southern part is known as the Malabar coast which is about 550 km long and 20-100 km wide. The maximum extension of the Malabar coast is found in the valleys of the Beypore, the Ponnani (draining through Palghat), the Periyar and Pamba Achankovil rivers. This coast is characterised by sand dunes. Along the coast, there are numerous shallow lagoons and backwaters—Kayals and Teris. These lagoons are linked together to facilitate navigation through small country boats. Here, Vembanad and Asthamudi are the important lagoons of the Malabar coast. The coast shows evidence of emergence.