Use the syntax {{Period start|period name|rounding (optional)}}

{{Period start|Cretaceous}}

produces:

145


{{Period start|Cretaceous|-1}}

produces:

150
change

References

change
  • Periods from the International Commission on Stratigraphy's stratigraphical timescale.
  • Burgess shale age from Butterfield, Nicholas J. (December 2006). "Hooking some stem-group "worms": fossil lophotrochozoans in the Burgess Shale". BioEssays. 28 (12): 1161–1166. doi:10.1002/bies.20507.
  • Cambrian stages from English, Adam M.; Babcock, Loren E. (September 2010). "Census of the Indian Springs Lagerstätte, Poleta Formation (Cambrian), western Nevada, USA". Palaeogeography, Palaeoclimatology, Palaeoecology. 295 (1–2): 236–244. doi:10.1016/j.palaeo.2010.05.041.
  • Mayanian dates from Khomentovsky, V; Nagovitsin, K; Postnikov, A (2008). "Mayanian (1100–850 Ma) – Prebaikalian Upper Riphean of Siberia". Russian Geology and Geophysics. 49 (1): 1. doi:10.1016/j.rgg.2007.12.001.