Changes

Periods from the [http://www.geomorph.org/sp/arch/ISChart2009.pdf International Commission on Stratigraphy's stratigraphical timescale].

Periods from the [http://www.geomorph.org/sp/arch/ISChart2009.pdf International Commission on Stratigraphy's stratigraphical timescale].

Burgess shale age from {{cite journal| last=Butterfield |first=N. J. |year=2006 |title=Hooking some stem-group "worms": fossil lophotrochozoans in the Burgess Shale |journal=Bioessays |volume=28 |issue=12 |pages=1161–1166 |doi=10.1002/bies.20507}}

Burgess shale age from Butterfield, N (2006). Hooking some stem-group "worms": fossil lophotrochozoans in the Burgess Shale. ''Bioessays'' '''28''', 1161–1166. {{doi|10.1002/bies.20507}}.

Cambrian stages from {{cite doi|10.1016/j.palaeo.2010.05.041}}

Cambrian stages from {{doi|10.1016/j.palaeo.2010.05.041}}

Mayanian dates from {{cite journal | doi = 10.1016/j.rgg.2007.12.001 | title = Mayanian (1100–850 Ma) – Prebaikalian Upper Riphean of Siberia | year = 2008 | last1 = Khomentovsky |first1=V. | journal = Russian Geology and Geophysics | volume = 49 | issue = 1 | pages = 1 | last2 = Nagovitsin | first2 = K. | last3 = Postnikov | first3 = A }}

Mayanian dates from Khomentovsky (2008). Mayanian (1100–850 Ma) – Prebaikalian Upper Riphean of Siberia. ''Russian Geology and Geophysics'' '''49''' (1).  {{doi|10.1016/j.rgg.2007.12.001}}.

==Period templates==

==Period templates==