Darwen River Section

Also within

Lancashire County

Condition (Natural England)

Habitats

Fast flowing river and stream

Geology & landscape

Geological Period: Carboniferous

Description

Area, 5.6 hectares 13.9 ac Description, 7 kilometres east of Preston the River Darwen has cut down through the rock strata to produce a site the geological interest of which may be defined as follows, The bed and banks of the River Darwen here provides one of the finest sections available in Britain of Middle Namurian rocks of Carboniferous age, originally laid down about 320 million years ago. These sandstones and shales accumulated over a long period of time, primarily from the sediment carried by a major river which built a vast delta southwards from uplands in Scotland. Within these deposits, however, geologists have recognised thin bands of marine clay indicating brief periods when the delta was submerged beneath the sea. These marine bands contain the fossilised remains of sea creatures known as goniatites which evolved rapidly during the Carboniferous and are thus of great value for the accurate dating of rocks of this age; the River Darwen section contains a number of these important marine bands. The high quality of this section is widely recognised by geologists and has led it to be proposed as the standard for three, the Chokerian, Alportian and Kinderscoutian, of the major divisions Stages of the Carboniferous Period of geological time. In general, the River Darwen section is a most important site of great value as a reference section for geological study.

Plant communities