Sandstone and mudstone interbeds at the top of the shelves

This is an outcrop of rocks from the Sagamiko Group, which constitutes the Shimanto Belt accretionary complex. The rocks are dark gray to bluish-gray mudstone and sandstone, with some of the mudstone having been transformed into hornfels by heat. The interbedded sandstone and mudstone in this area exhibit clearly defined bedding planes.

Because the rocks are hard and firmly consolidated, the surrounding mountains have a steep topography. The Nakama River flows in a straight line, forming a deep V-shaped valley.