与深海相放射虫硅质岩相伴，则夹有玄武岩（细碧岩）层。
1·Thin basalt (spilite) layers are often interbedded in those deep Marine radiolaria-bearing siliceous rocks.
与深海相放射虫硅质岩相伴，则夹有玄武岩(细碧岩)层。