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长江下游两岸的构造单元不一,右岸河没滩平原狭窄,沿江两岸地区多山地、丘陵和阶地。南京以下主要由下蜀土组成的底层物质,一般分为两级。左岸与右岸相反,地貌形态呈现广阔的低平原,主要由疏松沉积物所组成。一般说来,石质山地或丘陵所构成的河岸由不易受冲刷,胶结性强、密实度高的更新统粘土、亚粘土和砾石层组成的长江古阶地,其抗冲刷能力也比全新统的疏松沉积物组成的阶地强很多。
The structural units on both banks of the lower reaches of the Yangtze River are different. The plains on the right bank and the non-bank are narrow and mountainous, hills and terraces cross the banks of the Yangtze River. Nanjing, the following mainly composed of the underlying material soil, generally divided into two levels. On the contrary, on the left bank and on the right bank, the topography shows a vast low plain composed mainly of loose sediments. In general, the banks of stony mountains or hills are dominated by the ancient terraces of the Yangtze River, which are not susceptible to erosion, cementation and high compaction of the Pleistocene clays, loam and gravel, and are also more scouring-resistant than the Holocene Loose sediments form a lot of terraces.