In stratigraphy, the describing of stratigraphic units in terms of the kind of rock or fossil they contain. In practice it is the lower-ranking units, e.g. zones, that are defined typologically. Compare hierarchical method.
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。