Early Jurassic

Age ( Ma)
Cretaceous Lower/
Berriasian younger
Jurassic Upper/
Tithonian ~145.0 152.1
Kimmeridgian 152.1 157.3
Oxfordian 157.3 163.5
Middle Callovian 163.5 166.1
Bathonian 166.1 168.3
Bajocian 168.3 170.3
Aalenian 170.3 174.1
Toarcian 174.1 182.7
Pliensbachian 182.7 190.8
Sinemurian 190.8 199.3
Hettangian 199.3 201.3
Triassic Upper/
Rhaetian older
Subdivision of the Jurassic system
according to the ICS, as of 2017. [1]
Massive cliffs in Zion Canyon consist of Lower Jurassic formations, including (from bottom to top): the Kayenta Formation and the massive Navajo Sandstone.

The Early Jurassic epoch (in chronostratigraphy corresponding to the Lower Jurassic series) is the earliest of three epochs of the Jurassic period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma (million years ago), and ends at the start of the Middle Jurassic 174.1 Ma.

Certain rocks of marine origin of this age in Europe are called " Lias" and that name was used for the period, as well, in 19th-century geology. [2] In southern Germany rocks of this age are called Black Jurassic.

Origin of the name Lias

There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias limestone from South Wales was used throughout North Devon/North Cornwall as it contains calcium carbonate to fertilise the poor quality Devonian soils of the West Country); the Cornish would pronounce the layers of limestone as 'laiyers' or 'lias'.

Other Languages
Deutsch: Unterjura
Esperanto: Liaso
euskara: Lias
Lëtzebuergesch: Lias
magyar: Kora jura
Nederlands: Lias (geologie)
norsk nynorsk: Tidleg jura
polski: Jura wczesna
Simple English: Lower Jurassic
srpskohrvatski / српскохрватски: Donja jura
svenska: Äldre jura
українська: Лейас
Tiếng Việt: Jura Sớm