Chain corals became extinct at the close of the Silurian, but other corals were extremely common in the Devonian seas.
The banks of the brook at this spot are composed of purple-brown slate (Silurian).
These beasts were such creatures as might have peopled the earth in the Silurian age.
So the old Silurian seas were opened up to breed the fish in.
Lingula has not risen since the Silurian epoch, whereas other molluscs may have risen.
He was already old in society, and belonged to the Silurian horizon.
In Figs. 12 and 13 I have placed side by side two Silurian fossils which are found in the same geological horizon.
The Wenlock limestone (Silurian) contains an abundance of corals.
Again, the recent discovery of plants rather low down in our Silurian beds is very important.
The Silurian rocks of the county measure about 300 feet in thickness.
1708, "pertaining to the Silures," from Latin Silures "ancient British tribe inhabiting southeast Wales." Geological sense is from 1835, coined by Sir Roderick Impey Murchison (1792-1871) because rocks of this period are especially frequent in Wales.
The third period of the Paleozoic Era, from about 438 to 408 million years ago. During this time glaciers that formed during the late Ordovician melted, causing sea levels to rise. The first coral reefs, fish with jaws, and freshwater fish appeared, and jawless fish continued to spread rapidly. The first vascular plants also appeared, as did land invertebrates including relatives of spiders and centipedes. See Chart at geologic time.