Abstract
At the northernfoot of Yokodake, which is 2, 060m above the sea level, there is a small lake, Kikko-Ike. A typical development of sorted polygon is seen there. Its order is 40-200cm.
Sorted polygon (photo) is also shaped at Kagamiga-Ike, a small lake to the east of Mt. Shirane, 1, 780m above the sea level. And its order is 70-130cm.
In each example of sorted polygon subsoil of the part shown inside the circle (*Fig) is well sorted. In the process of the formaton of these sorted polygon, supply of plenty of water and frequent freeze-thaw action has apparently played an important role.
