Orkney Islands in Scotland from the shale, traces of the chemical precursors to life can still be detected, although the heat has changed the composition of this piece of shale.

• 在来自苏格兰奥克尼群岛的泥岩中，生命体的化学痕迹仍可以被探测到，尽管热量改变了这块泥岩的成分。