We examined the formation processes of the Ametaki lacustrine deposits to develop a learning method for high school students. We postulated the following formation processes: 1) Either dacite lava flowed into the lake or the lake was formed on dacite lava directly. 2) Dacite lava was covered by Ametaki lacustrine deposits. 3) Andesite lava flows covered the Ametaki lacustrine deposits. 4) Following this, deformations occurred in the Ametaki lacustrine deposits due to stress in the area. We expect to be able to understand the formation processes of the Ametaki lacustrine deposits based on the results of observations by the students.