A Russian-Kazakhstanian stage (524–518.5 Ma ago) of the Early Cambrian epoch, preceded by the Atdabanian and followed by the Toyonian.
科学参考收录了60776条科技类词条，基本涵盖了常见科技类参考文献及英语词汇的翻译，是科学学习和研究的有利工具。