The Sahyadris or Western Ghats run parallel to the western coast for about 1,600 km in north- south direction from the mouth of the Tapi river to Cape Camorin. TTic.se arc block mountains formed due to the downwarping of a part of the land into the Arabian Sea.
Their western slope is steep and precipitous while the eastern slope is imperceptibly gradual and step like. Sahyadris form the real watershed of the Peninsula. All the important Peninsular Rivers like Godavari, Krishna, Kaveri and Tambraparni and the important tributaries rise from these hills and flow eastwards into the Bay of Bengal.
The western rivers swiftly flowing into the Arabian Sea with steep gradient and narrow gorge like valley form a number of waterfalls (Gersoppa or Jog falls 250 m high on the Sharvati River). Their average elevation is from 1,000 to 1,300 m.
The Sahyadris upto 16° N latitude is mainly composed of basalt and has typical Deccan Trap like relief. In this portion rise the Godavari, Bhima and Krishna rivers (near Mahabaleshwar). The Satmala ridge branches off to the east between the Tapi and the Godavari, while Mahadeo ridge branches off between the Bhima and Krishna rivers. Harishchandragarh (1424 m), Mahabaleshwar (1438 m), Kalsubai (1646 m) and Salher (1567 m) are the important peaks in this section. Thalghat and Bhorghat are the important passes through which roads and railways run between the Deccan Plateau and the Konkan Plains.
South of Goa the Sahyadris are composed of granites and gneisses and have more rugged topography. Here Ghats are close to the coast and are thickly forested.
Their average elevation is 1220 m but several peaks arc higher than 1500 m, Kudremukh (1892 m), Pushpagiri (1714 m). InII Nilgiris the Eastern Ghatsjoin the Sahyadristofo a mountain knot whose highest point is Doddab (2637 m). Here charnokites dominate betwe Pushpagiri and Brahmagiri. South of Nilgiri lies the Palghat Gap (height 144 m, width 24 km) whio, connects Tamil Nadu with Kerala. South of Palghat’ Anaimundi (2695 m) is a knot which is joined byj three hills, viz. the Anaimalai Hills (1800-2000 m) in the north, the Palni Hills (900-1200 m) in the north-east and the Cardamom or Elamalai Hills in the south. River Periyar rises near Davar Malai (1922 m).
The Anaimalai constitutes a series of plateaus with rolling topography, intersected by deep glens and valleys and covered with thick forests of teak, ebony, rose wood and bamboos. Here hill slopes support tea, coffee, cinchona and cardamom plantations.
Tambraparni has its source near Agastya Malai forming a series of waterfalls (Banatirtham and Papanasam). Kodaikanal hill station (2195 m) is located on the southern edge of the Palni hills. The Western Ghats terminate about 20 km north of Cape Camorin.