Tonawandan

Смотреть что такое "Tonawandan" в других словарях:

• Geologic time scale — This clock representation shows some of the major units of geological time and definitive events of Earth history. The Hadean eon represents the time before fossil record of life on Earth; its upper boundary is now regarded as 4.0 Ga.[1] Other… …   Wikipedia

• Silurian — Geological period from=444 middle=429 to=416 o2=14 co2=4500 temp=17The Silurian is a geologic period and system that extends from the end of the Ordovician period, about 443.7 ± 1.5 Ma (million years ago), to the beginning of the Devonian period …   Wikipedia