A Russian stage (305–303.9 Ma ago) in the Pennsylvanian epoch, preceded by the Chamovnicheskian and followed by the Klazminskian (Gzhelian epoch).
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。