Automatically produce see also hatnote for geological categories that links to categories for adjacent time spans.
For test cases, see
<nowiki>{{</nowiki>#invoke:Geological time|seeAlso<nowiki>}}</nowiki> is the standard usage.
<nowiki>{{</nowiki>#invoke:Geological time|seeAlso|article_title<nowiki>}}</nowiki> performs a test for any article title. For example:
<nowiki>{{</nowiki>#invoke:Geological time|seeAlso|Category:Jurassic animals<nowiki>}}</nowiki> →
Two specialized entry points for finding time spans before and after the argument:
<nowiki>{{</nowiki>#invoke:Geological time|before|Jurassic<nowiki>}}</nowiki> →
<nowiki>{{</nowiki>#invoke:Geological time|after|Triassic<nowiki>}}</nowiki> →