However, these rivers have a sandy bottom, and the sand can hold water.

然而，这些河部是砂质，沙子可以容纳水。

In life, Fortey says, most of them probably simply lay upon the surface of the sandy sediment, like soft, structureless and inanimate flatfish.

“生活中，”福泰说，“它们大多数很可能就趴砂质沉积物表面，就像没有固定形状、毫无生气、软绵绵比目鱼那样。”

Just for a moment he hesitates, glancing up at the sandy textured rock.

他犹豫了，头望向那块砂质纹理岩石。

Sand dams are concrete barriers built across the bed of a seasonal river with a sandy riverbed.

沙坝是季节性河砂质河床上建造混凝土屏障。