■國。 砂岩.硅质岩灰岩交错层硅质岩砾石 Scour surface And Its Relation To The Sequence Of The Beds The sandstone beds are over the silicalite beds note the gravels in the bottom bed of the sandstonesScour surface And Its Relation To The Sequence Of The Beds The sandstone beds are over the silicalite beds, note the gravels in the bottom bed of the sandstones