1. The duration of previous geologic periods was difficult to determine. 以前很难确定地质期的持续时间。
2. Lyell's strategy for estimation of geologic dates was not very accurate. 莱尔估算地质年代的方法不是很准确。
3. Many scientists provided valuable research and input into the creation of the geologic time scale. 许多科学家为地质时间尺度的建立提供了有价值的研究和投入。
4. Three very large volcanoes are found on the Tharsis bulge, an enormous geologic area near Mars's equator. 在塔尔西斯高原上发现了三座非常大的火山。塔尔西斯高原是火星赤道附近一片广阔的地质区域。
5. Ocean sediments presented a much more complete geologic record of the Pleistocene than continental glacial deposits did. 相比于大陆冰川沉积物，海洋沉积物提供了更完整的更新世时期的地质记录。
