Green Geology

Dawlish cliffs are a stunning exposure of the New Red Sandstone, easily accessible by public transport and the South West Coast Path.   They are formed from aeolian (wind-blown) sand which was laid down in a desert in a continental interior in the Permian Period roughly 250 million years ago.

 

Walking south to north, starting at Coryton’s cove at the southern end of Dawlish's coast, Coryton Breccia (of many clast types including quartzite and pink feldspars) and Teignmouth Breccia (including Devonian and Carboniferous slates, cherts, and igneous rocks) can be seen there.  These were laid down in an alluvial fan.  A major fault at Coryton’s Cove brings these and the Dawlish Sandstone, which overlies them, together.

 

North of the railway station you see the sandstone cliffs by walking along the sea wall – there are railway lines between the sea wall and the cliffs so examination with a hand lens is not possible!  One word of warning:  The tide reaches right to the sea wall and in stormy conditions the waves can crash over it making access very dangerous.  The cliffs show large-scale cross-bedding, especially near Black Bridge.  The preserved stratification of these dune sands shows that they were migrating eastwards.  Easily visible in the cliffs is clear evidence of flash flooding, stream beds filled with larger clasts.  Wind-blown sands have then again been deposited above these ephemeral streams.  These were laid down horizontally but have become tilted along with the rest of the cliffs.

 

As the railway line turns north to Dawlish Warren, Langstone Rock displays the Exe Breccia, coarse sediments emplaced in an alluvial fan.  Langstone Rock is in fact the type section for this formation.  It may well be that the change from the wind-lain Dawlish Sandstone Formation to the water-lain Exe Breccia, which lies above it in stratigraphic terms, is evidence of climate change as rainfall increased at the end of the Lower Permian.

 

A natural arch is visible from the north side and also seen from here the start of the Jurassic Coast on the west side of the Exe presents opportunities for further exploration.

 

All told, Dawlish Cliffs are an essential site for understanding the processes through which aeolian sediments are laid down.

Text and photography (c):

Naomi Stevenson

 

Page updated March 2013

Useful links:

 

South West Coast Path

 

How to get there:

Bus, train or on foot via the South West Coast Path

 

Nearest railway station(s):  

Dawlish or Dawlish Warren (on sea front)

 

Accessibility:

Mainly level paths but steps or walk along beach to sea wall.  Step-free access is possible by going south from Dawlish Warren to Black Bridge.

Permian

 

Site of Special Scientific Interest (SSSI)

Dawlish Cliffs,Devon

Text and photographs:  Naomi Stevenson

Geology by public transport

Click to enlarge