slate bed

• 板岩层

slate bed的用法和样例：

例句

1. There's a bed of rock a few feet below the surface.
   地壳以下几英尺的地方便是岩层。
2. Exaggerated sections distort the shapes of folds as well as bed thickness.
   比例放大的剖面歪曲褶皱的形态和岩层厚度。