This template simplifies the task of creating a geological range (as per {{Geological range}}) based on one or two named geological periods when you want the period names to be wiki-linked.
It does not have the flexibility of the full {{Geological range}} template, which should always be used to create a geological range in any other way (e.g. based on numerical dates, or with an extended range).
The full template must be used when the name of the geological period is not the same as title of the page to be linked, e.g. Ludlow links to the town rather than the Ludlow epoch.
There are two ways of using the template:
{{Geological range/linked|period name|link1=period article name (optional)|ref=reference (optional)}}
{{Geological range/linked|first period name|second period name|link1=first article name (optional)|link2=second article name (optional)|ref=reference (optional)}}
{{Geological range/linked|Silurian}}
produces:
{{Geological range/linked|Wenlock|link1=Wenlock (Silurian)}}
produces:
{{Geological range/linked|Silurian|Early Permian}}
produces:
{{Geological range/linked|Middle Devonian|ref=<ref name="ref">Dummy reference</ref>}}
produces:
{{Geological range/linked|Wenlock|Ludlow|link1=Wenlock (Silurian)|link2=Ludlow epoch|ref=<ref name="ref" />}}
produces:
Note that this template does not provide any of the other parameters of {{Geological range}}.
If you have specified the parameters correctly and this template generates an error, it is likely to be because the period is missing from {{next period}} or {{period start}}. Please go ahead and add it in the appropriate place (once you've checked your spelling!).
You also need to add the period to {{period start error}} so that other templates which display geological dates, such as {{period span}} will work properly with this new period name.
For documentation on the sources of the dates and other information, see Template:Period start.