The Early Ordovician System is composed mainly of a series of carbonate platform deposits interbedded with shale and is especially characterized by a large numb
【正】The Qaidam Basin is a large intermontane depression in Qinghai Province,China,which located on the northern margin of the Tibet plateau,and surrounded by
According to the classic doctrine of angiosperm evolution,the archetype carpel in angiosperms is of plicate form.However,this concept is facing increasing chall