With 2 Plates During the recent five years I have joined several field parties in the carrying out of geological reconnaissances in regions between the valley of the Huangho and of the Yangtze and in the Sino-Tibetan borderland. This vast territory can be divided into six major geological units, easily recognizable both in structure and relief. They are: With 2 Plates During the recent five years I have joined several field parties in the carrying out of geological reconnaissances in regions between the valley of the Huangho and of the Yangtze and in the Sino-Tibetan borderland. This vast territory can be divided into six major geological units, easily recognizable both in structure and relief. They are: