The hills consist of bluish-gray granites, with peaks averaging 3,800–4,000 feet (1,300–1,350 m). About 50 miles (80 km) wide and 20 miles (32 km) long, they are bisected into eastern and western sections by the Cheyyar and Agaram rivers, tributaries of the Palar. "The Barahmahal hills to the west are somewhat bare, but the Jawadhi are clothed in verdure to the very summit on the east: towards sunset the whole range puts on a purple tinge like heather bloom. The sharper shadows mark out minor ranges and valleys, which in the midday merge in the mass of the range, and beyond Bommaikuppam, looking from Tirupatur, a silvery cascade may be seen, shining bright in the setting sun.".