While recognition of the distinct Ordovician Period was slow in the United Kingdom, other areas of the world accepted it quickly.

Beginning in the Ordovician Period, mountain building intermittently proceeded in the eastern part of the Appalachian region throughout the rest of the era, bringing in new sediments.

The Silurian is a geologic period and system that extends from the end of the Ordovician Period, about 443. 7 ± 1. 5 million years ago ( mya ), to the beginning of the Devonian Period, about 416. 0 ± 2. 8 mya.

These layers were the result of an Ordovician Period sea which covered east-central Minnesota 500 million years ago.

During the middle Ordovician Period ( about 480-440 million years ago ), a change in plate motions set the stage for the first Paleozoic mountain building event ( Taconic orogeny ) in North America.

Corals, including some major extinct groups Rugosa and Tabulata, have been important reef builders through much of the Phanerozoic since the Ordovician Period.

The earliest known fossil vertebrates were heavily armored fish discovered in rocks from the Ordovician Period about 500 to 430 Ma ( megaannum, million years ago ).

Two land masses collided at the end of the Ordovician Period about 466 million years ago.

Some dispersed, fragmentary fossils of disputed affinity, primarily spores and cuticles, have been found in rocks from the Ordovician Period in Oman, and are thought to derive from liverwort-or moss-grade fossil plants ().

The fossils are of primitive fish and date back 450 million years to the Ordovician Period.

The game is divided into five distinct geological periods: the Cambrian Period and the Ordovician Period of the Paleozoic Era (" The World Before Land ") from 500 million years ago to 450 million years ago, then the Carboniferous period (" Early Creatures of Land "), the Mesozoic Era (" Age of Dinosaurs "), the late Neogene period (" Ice Age "), and finally the early Neogene period (" Early Man ").

The limestone formed during the Ordovician Period approximately 450 to 500 million years ago, but it was formed at the bottom of a relatively shallow ocean that then covered what is today Rockingham County, Virginia.

The crater is 6 km in diameter, and fossils found in the rock filling the crater suggest it dates to the middle Ordovician Period, about 455 to 430 million years ago.

Four great ice ages have swept away all traces of the more recent Mesozoic and Cenozoic eras in the Twin Cities area, however standing at the upper falls, one is standing directly on the Platteville Limestone Formation laid down during the Ordovician Period of the Paleozoic Era.

During the Ordovician Period, about 450 million years ago, the North American continent was situated along the equator, and a warm shallow sea covered much of Minnesota.

The origins of the teleostomes are obscure, but their first known fossils are Acanthodians (" spiny sharks ") from the Late Ordovician Period.

* Map showing Avalonia in the Ordovician Period

The major extinction event marking the end of the Ordovician Period reduced the diversity of all trilobite orders with most asaphid families disappearing.

They belong to the taxon Ostracodermi, and their fossils are found in the Ordovician and Devonian Period strata of North America and Europe.

Many date to the Early Cambrian Period, but the order was extant through the Late Ordovician.

The Hirnantian is the seventh and final internationally-recognized stage of the Ordovician Period of the Paleozoic Era.

Some time during the Ordovician period ( which started around ) one or more streptophytes invaded the land and began the evolution of the embryophyte land plants.

In the Late Ordovician ( about 450 million years ago ) continental collision started between Avalonia and Baltica.

There are indications that the Bohemian Massif started moving northward from the Ordovician onward, but many authors place the accretion of the Armorican terranes with the southern margin of Laurussia in the Carboniferous Hercynian orogeny ( about 340 million years ago ).

Radiolaria have left a geological record since at least the Ordovician times, and their mineral fossil skeletons can be tracked across the K – T boundary.

# Ordovician – Silurian extinction event ( End Ordovician or O-S ): 450 – 440 Ma at the Ordovician-Silurian transition.

Production was found in the Ordovician Wilcox Sand at depths of ~ 6000 ' with initial production rates as high as.

Worldwide sea levels were at their all-time maximum in the Ordovician ; as the sea retreated, erosion inevitably began.

The bedrock underlying Florenceville-Bristol at its oldest is part of the White Head Formation consisting of limestone and calcareous shales of Late Ordovician to Early Silurian in age.

The upper layer of the hill consists of Ordovician limestone ( thickness about 5 m ), which is also the main rock exposed at the cliff.

A metre-wide dyke of diorite also runs through the exposed rocks of the quarry, possibly of late Ordovician age, which places it at a similar age to the Mountsorrel granite formations.

The strata have been detected in late Ordovician rock strata of North Africa and then-adjacent northeastern South America, which were south-polar locations at the time.

The Shakopee dolomite at the center of the structure is about 450 million years old ( Ordovician period ) and is uplifted about 2, 000 feet higher than the level of the same rock in the surrounding area.

Nautiloids remained at the height of their range of adaptations and variety of forms throughout the Ordovician, Silurian, and Devonian periods, with various straight, curved and coiled shell forms coexisting at the same time.

This happened at the end of the Ordovician and during the early Silurian.

In general, the highest mountains are at the south end of the lake and are composed of strata that are of Cambrian, Ordovician and Devonian ages-rocks that were deposited between 600 million and 350 million years ago.

The volcanogenic massive sulfide ore deposit is located at the border of the Ordovician to the Llandovery epoch the ore is covered by an overlying layer of volcanic rhyolites.

For example, sea level was low at the time of formation of Pangaea ( Permian ) and Pannotia ( latest Neoproterozoic ), and rose rapidly to maxima during Ordovician and Cretaceous times, when the continents were dispersed.

These formations were located at the very top of Ordovician deposits, and were dominated by a fauna which included brachiopods, trilobites, and other “ shelly ” or hard-coated animals.

In the Early Ordovician epoch ( about 480 million years ago ) the microcontinent ( a small fragment of continental lithosphere ) Avalonia ( at present lithosphere that is scattered over the east of New England, the south of Newfoundland, parts of New Brunswick and Nova Scotia, southern Ireland, most of England and Wales, the low countries and northern Germany ) began to separate from the northern margin of Gondwana.

The Ordovician – Silurian extinction event, or quite commonly the Ordovician extinction, was the second-largest of the five major extinction events in Earth's history in terms of percentage of genera that went extinct and second largest overall in the overall loss of life.

Through the Late Ordovician outgassing from major volcanism was balanced by heavy weathering of the uplifting Appalachian Mountains, which sequestered CO < sub > 2 </ sub >.

A major current ( 2004 – 08 ) project of UNESCO's International Geoscience Programme ( IGCP ), following a successful probe of the Ordovician biodiversification, has as its major objective to seek the possible physical and chemical causes, related to changes in climate, sea level, volcanism, plate movements and extraterrestrial influences, of the Ordovician biodiversification, this end-Ordovician extinction, and the ensuing Silurian radiation.

The major rocks of the Kitzbühel Alps divide into two groups by age, the older rocks probably dating to the Ordovician period.

Zhuravlev, " Structure and diversity of oldest sponge-microbe reefs: Lower Cambrian, Aldan River, Siberia ", Geology 23. 7 ( July 1995: 649-52 ) A major radiation occurred in the Lower Cambrian and further major radiations in the Ordovician possibly from the middle Cambrian.

Brachiopods, for example, underwent major bursts of evolutionary radiation in the Early Cambrian, Early Ordovician, to a lesser degree throughout the Silurian and Devonian, and then again during the Carboniferous.

The age of the Highland Boundary Fault has been inferred to be between Ordovician to Middle Devonian and it has been interpreted as a graben-bounding normal fault, a major sinistral strike-slip fault, a NW-dipping reverse fault or terrane boundary through time.

However, the thelodonts ( as well as the conodonts, placoderms, acanthodians, and chondrichthyans ) are the second major group which are believed to have emerged in the middle Ordovician and lasted near the Late Devonian period.