The earliest era of the Priscoan, covering the formation of the Earth and ending around 4550 Ma ago (Harland et al., 1989). The name is no longer used.
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。