The Ara River of Saitama, Japan flows through the Chichibu Mountains before crossing the Kanto Plains and onwards to Tokyo Bay. In the mountains the river cuts down through some old metamorphic rocks that were raised up as the mountains were uplifted. The rocks have veins of quartzite running through them. Around the town of Nagatoro some of the best examples of this rock have been exposed and make an impressive scenic view with the green waters of the river. This detail was found a short distance downstream from the tourist destination of Nagatoro.