Silurian

The Silurian is the geologic period as living as system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years before Mya, to the beginning of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start & end are alive identified, but the exact dates are uncertain by a few million years. The base of the Silurian is vintage at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out.

One important event in this period was the initial established of terrestrial life: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding together with diversifying along with glomeromycotan fungi, and three groups of arthropods myriapods, arachnids and hexapods became fully terrestrialized.

A significant evolutionary milestone during the Silurian was the diversification of jawed fish and bony fish.

History of study

The Silurian system was first identified by British geologist , . In 1835 the two men made a joint paper, under the tag On the Silurian and Cambrian Systems, Exhibiting the grouping in which the Older Sedimentary Strata Succeed regarded and transmitted separately. other in England and Wales, which was the germ of the advanced geological time scale. As it was number one identified, the "Silurian" series when traced farther afield quickly came to overlap Sedgwick's "Cambrian" sequence, however, provoking furious disagreements that ended the friendship.

Charles Lapworth resolved the conflict by defining a new Ordovician system including the contested beds. An alternative draw for the Silurian was "Gotlandian" after the strata of the Baltic island of Gotland.

The French geologist Joachim Barrande, building on Murchison's work, used the term Silurian in a more comprehensive sense than was justified by subsequent knowledge. He shared the Silurian rocks of Bohemia into eight stages. His interpretation was questioned in 1854 by Edward Forbes, and the later stages of Barrande; F, G and H relieve oneself since been submission to be Devonian. Despite these modifications in the original groupings of the strata, this is the recognized that Barrande established Bohemia as a classic ground for the study of the earliest Silurian fossils.