Landform Story

The geological land formation of the Wye Valley is a fascinating story The Wye Valley AONB includes several Sites of Special Scientific Interest (SSSIs) noted for their geological features.

To gain an understanding of the rocks that lie beneath our feet have a look at the Geological Society's superb animation of the Rock Cycle which is a great starting point to understand more about the fascinating geology of the Wye Valley AONB.

  Wye Valley AONB Geology Map click for larger image

Woolhope Dome
We begin our geological journey in the north of the AONB in the area known as the Woolhope Dome where the oldest rocks in the area can be found. These rocks belong to a geological time period known as the Silurian dating between 444 to 416 million years ago.In the Silurian Period, more than 400 million years ago the area we now know as the Wye Valley was south of the equator and England and Wales were separated from Scotland by Iapetus Ocean. It was an age when life began to move from the sea to land, well before the time of amphibians, dinosaurs, mammals and birds.The warm, clear, shallow seas were teeming with life.  
Geologists studying fossils from Silurian rocks have been able to build up a picture of the life forms that existed in the shallow seas.

The Woolhope Dome, attracted a great deal of geological interest. It has offered the opportunity to study a range of rocks from  the earliest forms of life on earth Over time, the top of the dome shaped hill, has been worn down to reveal a mix of  rocks among them limestone’s, shales and sandstones, known collectively as sedimentary rocks. The oldest rocks of all in this area are the Llandoverian sandstones of Haugh Wood and Broadmoor Common.

Herefordshire Lowlands: Mordiford to Goodrich
The colour of the soil in this area of the Wye Valley is a rich rusty red and is largely created from red mudstones  and sandstones. The rocks in this area date from the Devonian geological period It is known as the age of the fishes with thousands of species of fish developing in the warm Devonian Seas.

The sandstone can be seen at its most imposing at the former river cliffs at Ross-on-Wye. As the underlying rocks from Mordiford to Goodrich are softer, this has allowed the river to meander across the gently rolling countryside. The soil deposited from the red sandstone by glacial melt water is fertile and it is in this area where farming has come to dominate the countryside.  

Into the Wye Gorge
The Wye Gorge is famed for its fabulous views. The river has cut through the limestone to form impressive river cliffs and It is here that the Devonian and Carboniferous geological ages meet. 

360- 286 million years ago,dense forests of tree ferns flourished in the area, and winged insects and amphibians became more common. The decaying trees of the swamps were to form coal measures of the future.

Around Symonds Yat, limestone and red sandstone meet. This leads to a countryside of hills and plains, as well as substantial meanders in the river which is still eroding the land. Where it has cut through limestone impressive river cliffs have formed that prove a great attraction and challenge to rock climbers.

Underground
The Wye valley has lots of interest for underground exploring. There are many rock shelters and what are known as solution caves, caves formed through the passage of water. A cave is a natural opening in the ground. It is usually big enough to let a person in, and extends beyond the zone of light. It can range in size from a small room to passages many miles long. Some of the well known caves in the area include King Arthur's Cave, Little Doward Caves, Symonds Yat East caves and Symonds Yat West caves (all in the area of Symonds Yat in Herefordshire). At St Arvans, near Chepstow, the underground watercourses have carved out long cave systems, which exit at Otter Hole at the base of Piercefield Cliffs. This is the only cave system in England or Wales which has to be reached through a tidal sump, making it an attractive to challenge for experienced cavers.

The gorge is an important district for palaeontologists and some of these caves and rock shelters have yielded evidence of how prehistoric human populations lived in the Wye Valley as nomadic hunters.