The dataset is made freely available for access, e.g. via the Internet. Either no third party data / information is contained in the dataset or BGS has secured written permission from the owner(s) of any third party data / information contained in the dataset to make the dataset freely accessible.
A boundary between geological divisons of time
Geochronological Boundary
Base Neoproterozoic Iii [Obsolete Name And Code: Use Ad]
Base Palaeoarchaean
Base Ectasian
Base Cryogenian
Base Ediacaran
Base Rhyacian
Base Stenian
Base Mesoarchaean
Base Neoarchaean
Base Orosirian
Base Proterozoic
Base Stratherian
Base Archaean
Base Mesoproterozoic
Base Neoproterozoic
Base Bavelian
Base Cromerian Complex
Base Weichselian
Base Eburonian
Base Holsteinian
Base Eemian
Base Elsterian
Base Menapian
Base Praetiglian
Base Saalian
Base Tiglian
Base Waalian
Base Carboniferous
Base Duckmantian
Base Westphalian B
Base Bolsovian
Base Westphalian C
Base Westphalian D
Base Arnsbergian
Base Gzhelian
Base Chadian
Base Arundian
Base Kinderscoutian
Base Mid Mississippian
Base Alportian
Base Pennsylvanian
Base Late Pennsylvanian
Base Mid Pennsylvanian
Base Holkerian
Base Asbian
Base Stephanian
Base Silesian [Obsolete Name And Code]
Base Westphalian
Base Brigantian
Base Yeadonian
Base Marsdenian
Base Famennian
Base Emsian
Base Mid Devonian
Base Pragian
Base Late Devonian
Base Givetian
Base Cambrian Stage 2
Base Cambrian Stage 4
Base Cambrian Stage 9
Base Cambrian Stage 10
Base Cambrian Series 2
Base Cambrian Series 3
Base Comley
Base St David'S
Base Drumian
Base Furongian
Base Guzhangian
Base Merioneth
Base Phanerozoic
Base Bartonian
Base Eocene
Base Late Eocene
Base Mid Eocene
Base Oligocene
Base Late Oligocene
Base Late Paleocene
Base Mid Paleocene
Base Cenozoic
Base Jurassic
Base Bajocian
Base Callovian
Base Kimmeridgian
Base Pliensbachian
Base Tithonian
Base Mid Jurassic
Base Bathonian
Base Portlandian [Obsolete Name And Code]
Base Sinemurian
Base Toarcian
Base Late Jurassic
Base Volgian [Obsolete Name And Code: Use Ji]
Base Cretaceous
Base Albian
Base Barremian
Base Campanian
Base Hauterivian
Base Maastrichtian
Base Coniacian
Base Aptian
Base Santonian
Base Turonian
Base Late Cretaceous
Base Valanginian
Base Mesozoic
Base Neogene
Base Neogene [Obsolete Code: Use N]
Base Burdigalian
Base Messinian
Base Late Miocene
Base Mid Miocene
Base Pliocene [Obsolete Code: Use Np]
Base Late Pliocene
Base Pliocene
Base Serravallian
Base Ordovician
Base Caradoc
Base Ashgill
Base Caradoc [Obsolete Code: Use O4]
Base Llandeilo [Obsolete Name And Code: Use O3]
Base Darriwilian
Base Llanvirn
Base Fennian
Base Hirnantian
Base Whitlandian
Base Burrellian
Base Katian
Base Longvillian
Base Late Ordovician
Base Marshbrookian
Base Mid Ordovician
Base Onnian
Base Cheneyan
Base Arenig
Base Cautleyan
Base Llanvirn [Obsolete Code: Use Oe Or O2]
Base Rawtheyan
Base Streffordian
Base Soudleyan
Base Permian
Base Artinskian
Base Kungurian
Base Sakmarian
Base Tatarian [Obsolete Name And Code]
Base Late Permian [Obsolete Name And Code: Use Pul Or Pug]
Base Capitanian
Base Wordian
Base Guadalupian
Base Changhsingian
Base Lopingian
Base Quaternary
Base Quaternary [Obsolete Code: Use Q]
Base Ionian
Base Tarantian
Base Anglian
Base Beestonian
Base Cromerian
Base Devensian
Base Dimlington Stadial
Base Loch Lomond Stadial (Younger Dryas)
Base Windermere Interstadial
Base Baventian
Base Holocene
Base Ipswichian
Base Ludhamian
Base Marine Isotope Stage 1
Base Marine Isotope Stage 2
Base Marine Isotope Stage 4
Base Marine Isotope Stage 5a
Base Marine Isotope Stage 5b
Base Marine Isotope Stage 5c
Base Marine Isotope Stage 6
Base Marine Isotope Stage 7
Base Marine Isotope Stage 8
Base Marine Isotope Stage 9
Base Marine Isotope Stage 13
Base Marine Isotope Stage 14
Base Marine Isotope Stage 15
Base Marine Isotope Stage 16
Base Marine Isotope Stage 17
Base Marine Isotope Stage 18
Base Marine Isotope Stage 20
Base Marine Isotope Stage 22
Base Marine Isotope Stage 23
Base Marine Isotope Stage 24
Base Marine Isotope Stage 25
Base Marine Isotope Stage 26
Base Marine Isotope Stage 27
Base Marine Isotope Stage 28
Base Marine Isotope Stage 29
Base Marine Isotope Stage 30
Base Marine Isotope Stage 31
Base Marine Isotope Stage 32
Base Marine Isotope Stage 33
Base Marine Isotope Stage 34
Base Marine Isotope Stage 35
Base Marine Isotope Stage 36
Base Marine Isotope Stage 37
Base Marine Isotope Stage 39
Base Marine Isotope Stage 40
Base Marine Isotope Stage 41
Base Marine Isotope Stage 42
Base Marine Isotope Stage 43
Base Marine Isotope Stage 44
Base Marine Isotope Stage 45
Base Marine Isotope Stage 46
Base Marine Isotope Stage 47
Base Marine Isotope Stage 48
Base Marine Isotope Stage 49
Base Marine Isotope Stage 50
Base Marine Isotope Stage 51
Base Marine Isotope Stage 52
Base Marine Isotope Stage 53
Base Marine Isotope Stage 54
Base Marine Isotope Stage 56
Base Marine Isotope Stage 57
Base Marine Isotope Stage 58
Base Marine Isotope Stage 59
Base Marine Isotope Stage 60
Base Marine Isotope Stage 61
Base Marine Isotope Stage 62
Base Marine Isotope Stage 63
Base Marine Isotope Stage 65
Base Marine Isotope Stage 66
Base Marine Isotope Stage 67
Base Marine Isotope Stage 68
Base Marine Isotope Stage 69
Base Marine Isotope Stage 71
Base Marine Isotope Stage 72
Base Marine Isotope Stage 73
Base Marine Isotope Stage 74
Base Marine Isotope Stage 75
Base Marine Isotope Stage 77
Base Marine Isotope Stage 78
Base Marine Isotope Stage 79
Base Marine Isotope Stage 80
Base Marine Isotope Stage 81
Base Marine Isotope Stage 82
Base Marine Isotope Stage 83
Base Marine Isotope Stage 84
Base Marine Isotope Stage 85
Base Marine Isotope Stage 86
Base Marine Isotope Stage 87
Base Marine Isotope Stage 88
Base Marine Isotope Stage 90
Base Marine Isotope Stage 91
Base Marine Isotope Stage 92
Base Marine Isotope Stage 93
Base Marine Isotope Stage 94
Base Marine Isotope Stage 96
Base Marine Isotope Stage 97
Base Marine Isotope Stage 98
Base Marine Isotope Stage 99
Base Marine Isotope Stage 101
Base Marine Isotope Stage 102
Base Antian/Bramertonian
Base Wolstonian
Base Thurnian
Base Pre-Pastonian
Base Hoxnian
Base Late Palaeozoic
Base Silurian
Base Aeronian
Base Ludfordian
Base Homerian
Base Pridoli
Base Telychian
Base Ludlow
Base Wenlock
Base Ladinian
Base Mid Triassic
Base Norian
Base Olenekian
Base Rhaetian
Base Late Triassic
Present Day