一、前言本文所指华北区,系辽东半岛—山东半岛以西,黄河中游以东,南以秦岭—大别山为界,北至阴山—燕山一线的广大地区。包括了华北平原、黄土高原的东部、伏牛山地和燕山山地部分地区。区内第四系发育良好,沉积类型多,并含丰富程度不同的软体动物化 I. Preface This refers to the North China region, the Department of Liaodong Peninsula - west of Shandong Peninsula, the middle reaches of the Yellow River to the east, south Qinling - Dabie Mountains as the boundary, north to Yinshan - Yanshan line of vast areas. Including the North China Plain, the eastern part of the Loess Plateau, Funiu Mountain and Yanshan Mountains in some areas. The Quaternary in the area is well-developed, with many depositional types and rich in molluscification