Abstract: The Radiolaria fossils are collected from siliceous gravel in conglomerate of Middle Devonian Sangejing Group in Dundunshan of Beishan area,Gansu province.The Radiolarians are identified primarily to be Inaniguttids,including two genus,the Inanigutta sp.and Inanibigutta sp.,which are primarily found in the strata of Ordovician-Silurian systems in the world,and Ordovician in North China.This discovery suggests silicalite containing Radiolaria of Lower Ordovician Shajing Group was been denuded,southward stransported and finally deposited in Dundun shan mola sses basin d ring the collision-orogenic period of Devonian in Beishan.Accordingly there existed collision-orogeney and amolasses basinin Devonian in Beishan area.