It is during these very periods of subsidence, that the deposits which are richest in fossils have been accumulated . 在这一沉陷期间，化石中最富含的沉积物堆积起来。
Simple organisms such as bacteria and alga have been found fossil in rocks more than 3000 m. y. old . 简单的生物，如细菌和藻类，它们的化石已在三十多亿年的岩石中发现。
This dependency between fossil and living types is well illustrated when we deal with extinct groups . 化石与现存类型之间的这种依赖关系在我们研究绝灭类群时是十分明显的。
At one point at an elevation of about 5500 feet above sea level the students pick up dozens of marine fossils . 学生们在海拔约5500英尺高度的地方，采集到了几十种海底化石。
Although the fossil record is incomplete, it still gives us a broad brush outline of what happened . 尽管化石记录不很完全，但仍然给我们一幅关于到底发生了什么事情的大体轮廓。
That specimen consists of a skull and the fossil impression of the brain of a 6-year-old child who died perhaps 2 million years ago . 这个标本是一个大约死于200万年前的6岁儿童的头骨和脑模化石。
If the first possibility is true, then the fossils were lifted to their present altitudes later by the plateau's upward thrust . 如果第一种可能性是确实的，那么化石是后来由于高原向上隆起才抬升到现在的高度。
But those fossils and robison's interpretations of them formed the initial groundwork for tracing early human evolution in africa . 但是这些化石以及罗宾逊对它们所作的解释奠定了在非洲追溯早期人类进化的初步基础。
The little marine animal neopilina, which was dredged up from the bottom of the pacific in 1952, looks practically identical to its ancestors presented as fossils over 50 million years ago . 1952年在太平洋底挖出来的小形海洋动物，新帽贝，看上去简直同保存了五亿多年的化石祖先一样。
This fossil is probably more than two million years 这化石可能超过二百万年了
