No frames

menu 1
menu 2
menu 3
menu 4
menu 5
menu 6
menu 7
menu 8
menu 9
menu 10

Geological Column

Age (millions of years ago)

Era
Period
Common Rocks
0 — 1.6

Cenozioc

(Recent Life)

Quaternary
Boulder clay from Ice Ages
1.6 — 23
Neogene
Clays and lignite around Lough Neagh
23 — 65
Palaeogene
Basalts, dolerites and granites
65 — 142

Mesozoic

(Middle Life)

Cretaceous
Chalk - widespread extinctions at the end of this period
142 — 206
Jurassic
Lias clay — Age of the dinosaurs
206 — 248
Triassic
Sandstones — first true mammals
248 — 290

Paleozoic

(Old Life)

Permian
Limestones - mass extinctions at the end of this period
290 — 354
Carboniferous
Carboniferous Limestone
354 — 417
Devonian
Old Red Sandstone
417 — 443
Silurian
Shale and greywache
443 — 495
Ordovician
Shale, sandstones, conglomerate
495 — 545
Cambrian
Schists
545 — 4600

Proterozoic

(First Life)

Precambrian

Oldest rocks in Ireland (at Inishtrahull, off Inishowen, Co. Donegal) 1750 Million years old

Gneiss

A mnemonic to learn the Geological Column from Precambrian to Cretaceous is:

Pregnant camels ordinarily sit down carefully, perhaps their joints creak. Basalt Schist Old Red Sandstone Old Red Sandstone Clay Limestone Limestone Granite Granite Greywache Greywache Sandstone Sandstone Sandstone Sandstone Shale Shale Shale Shale Shale Chalk Greywache Schist Dolerite Basalt Basalt Limestone Basalt Schist Old Red Sandstone Basalt Schist Clay Limestone Dolerite Granite Greywache Sandstone Chalk Shale