Silurian

Marine extinction intensity during the Phanerozoic
%
Millions of years ago
(H)
K–Pg
Tr–J
P–Tr
Late D
O–S

The blue graph shows the apparent percentage (not the absolute number) of marine animal genera becoming extinct during any given time interval. It does not represent all marine species, just those that are readily fossilized. The labels of the

Cooksonia, the earliest vascular plant, middle Silurian

Silurian sea bed fossils collected from Wren's Nest Nature Reserve, Dudley UK

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several million years. The base of the Silurian is set at a major extinction event when 60% of marine species were wiped out. See Ordovician-Silurian extinction events.

单词	Upper Silurian
释义	Upper Silurian 英语百科 Silurian The Silurian is a geologic period and system that extends from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by several million years. The base of the Silurian is set at a major extinction event when 60% of marine species were wiped out. See Ordovician-Silurian extinction events.
随便看	sub box的意思 subbrachial的意思 subbrachian的意思 subbrachycephalic的意思 subbranch的意思 sub branch的意思 subbranch bank的意思 subbranch的意思 subbranchial region的意思 sub branch office的意思 subbrand的意思 subbrands的意思 subbread的意思 subbreed的意思 subbreed的意思 subbrest的意思 sub broker的意思 subbronchial的意思 Subbryantodus的意思 subbuccal的意思 subbuccal gland的意思 subbulbous的意思 subbundle的意思 subbundle的意思 subbureau的意思

Upper Silurian

Silurian