Geological Period Time before present (millions of years)
Quaternary and Recent 1.8 to present
Tertiary 65 to 1.8
Cretaceous 145 to 65
Jurassic 213 to 145
Triassic 248 to 213
Permian 286 to 248
Carboniferous 360 to 286
Devonian 410 to 360
Silurian 440 to 410
Ordovician 505 to 440
Cambrian 544 to 505
Precambrian Time 4500 to 544 million years ago
Timescale uses breakpoints defined in the USGS 2001 scale