Editing Silurian (section)

==Paleogeography==
[[Image:Ordovicium-Silurian.jpg|thumb|left|[[Ordovician]]-Silurian boundary on [[Hovedøya]], [[Norway]], showing brownish late Ordovician [[mudstone]] and later dark deep-water Silurian [[shale]]. The layers have been overturned by the [[Caledonian orogeny]].]]
With the supercontinent [[Gondwana]] covering the equator and much of the southern hemisphere, a large ocean occupied most of the northern half of the globe.<ref name=Munnecke2010/> The high sea levels of the Silurian and the relatively flat land (with few significant mountain belts) resulted in a number of island chains, and thus a rich diversity of environmental settings.<ref name=Munnecke2010/>

During the Silurian, Gondwana continued a slow southward drift to high southern latitudes, but there is evidence that the Silurian icecaps were less extensive than those of the late-Ordovician glaciation. The southern continents remained united during this period. The melting of icecaps and [[glacier]]s contributed to a rise in sea level, recognizable from the fact that Silurian sediments overlie eroded Ordovician sediments, forming an [[unconformity]]. The continents of [[Avalonia]], [[Baltica]], and [[Laurentia]] [[Continental drift|drifted]] together near the [[equator]], starting the formation of a second [[supercontinent]] known as [[Euramerica]].

When the proto-Europe collided with North America, the collision folded coastal sediments that had been accumulating since the Cambrian off the east coast of North America and the west coast of Europe. This event is the [[Caledonian orogeny]], a spate of mountain building that stretched from [[New York (state)|New York State]] through conjoined Europe and Greenland to Norway. At the end of the Silurian, sea levels dropped again, leaving telltale basins of [[evaporite]]s extending from Michigan to West Virginia, and the new mountain ranges were rapidly eroded. The [[Teays River]], flowing into the shallow mid-continental sea, eroded Ordovician Period strata, forming deposits of Silurian strata in northern Ohio and Indiana.

The vast ocean of [[Panthalassa]] covered most of the northern hemisphere. Other minor oceans include two phases of the Tethys, the [[Proto-Tethys Ocean|Proto-Tethys]] and [[Paleo-Tethys Ocean|Paleo-Tethys]], the [[Rheic Ocean]], the [[Iapetus Ocean]] (a narrow seaway between Avalonia and Laurentia), and the newly formed [[Ural Ocean]].
[[File:Late silurian sea bed arp.jpg|thumb|Fossils of the late Silurian sea bed, England]]