Along a coast, an arch is made when caves on either side of a headland meet. Arches are temporary; roof falls cut off the seaward end of the arch, which is then left as a stack.
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。