The Palaeoproterozoic Erdaowa Group distributed in the north Hohhot, Nei Mongol is composed of metamorphic detrital sediment and carbonate with intermidiate basic volcanics.

• 出露于内蒙古呼和浩特北部的二道洼群,为一套陆源碎屑岩碳酸盐岩夹中基性火山岩变质建造。