In the pale light of the tunnel, 30-foot fossil traces of lycopsid gleam slickly in the shale roof like alligator skins.
在隧道内黯淡的灯光下，页岩顶部30英尺长的石松化石遗迹就像鳄鱼皮般发出柔滑的光亮。
2
The oil shale can be used as construction materials, such as high grade cement filler, light concrete bone material-pottery grain and light brick materials, etc.