抄録
The following three species of the typical Boreal-type brachiopod genus Yakovlevia occur from the Middle Permian of the Hida Gaien and South Kitakami Belts, Japan : Y. kaluzinensis Fredericks, Y. mammata (Keyserling) and Y. mammatiformis (Fredericks). The occurrence of Yakovlevia together with various many Boreal-and Tethyan-type brachiopods in the Middle Permian of the Hida Gaien and South Kitakami Belts provides evidence that these regions were a continental shelf at the eastern margin of the Sino-Korean block in the Middle Permian time.
