Permalink : http://hdl.handle.net/2115/36690

Seven halysitids are newly found and described from the Silurian Okuhinotsuchi Formation developed in the Shimoarisu district, Setamai region of Iwate Prefecture. Of them Halysites arisuensis is new to science. The Okuhinotsuchi Formation may be, based on halysitids, as a whole, Late Llandoverian to Wenlockian in age. In general halysitids described are much faunistically related to those of Southwest Japan and of Australia.