When did the trilobites reach their climax in the geological time scale?

Question

When did the trilobites reach their climax in the geological time scale?

Answer 1

Mainly Cambrian-Ordovician, but they are found in other periods during the Paleozoic as well.  

Here are the scales for trilobites (just keep scrolling):

http://www.trilobites.info/geotime.htm

Answer 2

http://www.trilobites.info/geotime.htm

http://www.trilobites.info/biostratigrap...

http://www.ohiohistorycentral.org/entry....

first 2 are best...