Charles Lyell made a good estimate of the Tertiary Period from the fossil record, but his method could not be extended to earlier geological periods.

查尔斯·莱尔根据化石记录对第三纪作出了很好的估计，但他的方法不能扩展到更早的地质时期。

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There are clickable links to each geological period providing accompanying text and graphics.

从这里可以点击进入各个地质时期，并伴有文字和图表说明。

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Human may define a geological period in the way dinosaurs — and their vanishing act — helped mark the Jurassic.

恐龙以及恐龙的消失是侏罗纪的标志，人类或许也会像它们那样定义一个地质时期。

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But we are the only species to have defined a geological period by our activity something usually performed by major glaciations, mass extinction and the colossal impact of objects from outer space, like the one that defines the upper boundary of the Cretaceous.

FORBES: On The Anthropocene Age

During a 4 months period, geological and hydrogeological data on the giant Guaran Aquifer System were critically revised and compiled.

UNESCO: Dublin Core

The Geopark's outstanding historical contribution, both in terms of the development of geological and archaeological sciences is astounding: from the Huttonian Theory, to the naming of the Devonian Period by Sedgwick and Murchison, and even Pengelly's discoveries informing worldwide public opinion as to the antiquity of man.

UNESCO: Global Geoparks