绪言 震旦纪作为一个地质时代的纪,在我国许多地质文献中,都是以葛利普规定的“在寒武纪地层之下从较老的变质岩中分出的未变质的或轻微变质的沉积岩系”为其相应的地层。本篇报告中说的震旦纪和震旦纪地层也从这个规定。不过应该声明:我们这样做,并不是认为这个规定合理,只是由於在本报告中所涉及的方面没有关於地质纪的讨论。至於葛利普的这个规定,顺便说,是不合理的。把震旦纪比做寒武纪以下五台系或泰山系以上的沉积岩系生成的时代,震旦纪就失去了时间上的固定性;把这个沉积 INTRODUCTION The Sinian, as a geologic epoch, has been identified in many geologic literature in our country as the basis of the “unconfined or slightly altered sedimentary rocks subducted from older metamorphic rocks below the Cambrian strata Department ”for its corresponding strata. The Sinian and Sinian strata mentioned in this report also follow this stipulation. However, it should be stated that in doing so, we do not consider this provision reasonable but simply because there is no discussion of geology in the areas covered in this report. As for Gripp's provision, by the way, it is unreasonable. In the era when the Sinian was compared to the Lower Cretaceous or Lower Cambrian sedimentary rock series, the Sinian lost its temporal stability; this deposition