Leighton Road Cutting
Also within
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| ST702437 | — | Unfavourable No Change | 0.52 | 2010-05-19 |
Geology & landscape
Geological Feature: Fissure · Geological Period: Carboniferous, Jurassic · Rock Type: Carboniferous Limestone, Limestone
Description
Area, 0.6 ha. 1.4 ac. Description Leighton Road Cutting provides exposure of a series of early Jurassic limestones, of Lower Lias age, which are the only known outcrops of these particular rocks to occur in a normal horizontally bedded sequence in the Mendips. At all other localities where these particular rocks have been recognised, they occur as fissure in fillings, whose exact mode of origin had been rather problematic within the Carboniferous Limestone. The discovery of the Leighton Road Cutting sections enabled geologists to understand, at last, how the fissure infills seen widely throughout the Mendips had been formed. The rocks seen at Leighton consist of a series of bedded limestones, belonging to the divisions of the Jurassic known as the Sinemurian and Pliensbachian Stages. Exactly similar rock types, yielding similar fossils, are seen in many fissure infills in the Mendips, but the exact mode of formation and age of the fissure infills had always been uncertain. The discovery of similar rocks and fossils in normal horizontal sequence at Leighton enabled geologists to interpret the ways in which the fissures had formed and the Leighton site is thus of very great importance.