泥盆紀の日本三葉虫群とその古地理論上の意義

Abstract

In Japan trilobites are profuse in the Lower Devonian Fukuji Formation in the Hida plateau, followed by the Middle Devonian ones in the Nakazato Formation in the Kitakami Mountains where they declined in the late Devonian Tobigamori age. These Lower Devonian ones are intimate to the contemporaries in Manchuria and Mongolia, while the later ones bear relationship with those in South China and Southeast Asia, though in the lessened degrees.