Cycle Tour 1

Ice Age legacy | back to map
This tour is an adventure to explore the legacy of the Ice Age in the west of Herefordshire – including the country north of the Wye and up to the Arrow valley. Action by glaciers in different ice ages over the last half-million years have formed a glacially eroded landscape of upstanding hills separated by lowlands mostly plastered with a veneer of sediment up to 30 metres thick.

Distinctive landscape features
Distinctive landscape features are mostly from the most recent Ice Age and gradually emerged from the ice from about 20,000 years ago. Deposits include the distinctive hummocky moraines (mounds of glacial debris) in which most of the ponds from Ice Ages are found.

Meltwater gorges
Meltwater pouring east from the ice margin led to extensive deposits of sand and gravel that underlie the western side of the Lugg Valley and much of Hereford city. As the ice retreated, the rivers Wye, Arrow and Lugg re-established themselves, in several places cutting down to form new courses with small gorges.

Area covered by Herefordshire ice lobe
Overview of the area formerly covered by the Herefordshire ice lobe in relation to modern settlements.
The shaded areas have many Ice Age ponds, mostly in hummocky moraine. The Letton Basin, in which the Sturts Reserves are located, is an exception, since this area is a flat, former lake floor.

Alternate start points | back to map
If arriving by train, the route starts at Hereford Station. Cyclists should navigate with the map in the app or a GPS device to reach site 1 (download a .gpx file of the route).

If bringing your cycle by car, go straight to Site 1 on the Breinton Road, and park on the roadside there.
Grid reference SO498398, postcode HR4 0LJ. The S on the map marks the location of a car park (pay and display) which you could use as a start point.

1:  Ice Front | back to map
Pause on your bike around here.
You have now met the eastern limit reached by the ice.
The next image is a reconstruction of what it would have looked like.

This spot around 22,00 years ago
A reconstruction of how this location may well have looked around 22,000 years ago, at the edge of the ice front. We know the ice reached here because the British Geological Survey found a thin deposit of a stony clay (called “till”) that was laid down by the ice.

Limit of Herefordshire glacier
On this Google Earth view you can see how your current location (Site 1) marks the eastern limit of the Herefordshire glacier in the last Ice Age.

Sands and gravels
This part of the route lies on sand and gravels that were deposited by rivers (“outwash streams”) draining the glacier that lay ahead to the west. Data from boreholes shows that these sands and gravels filled a valley here along which the “Proto-Wye” river used to flow before the last Ice Age. As you can see on the aerial view, here the road runs for 300 m on the eroded edge of a terrace of the River Wye. A terrace is a former floodplain of the Wye formed when the valley was not so deep.

Importantly, at site 1, you have now met the eastern limit reached by the ice. The British Geological Survey have found a glacial deposit (called “till” or “boulder clay”) in the area of the waterworks (just ahead from Site 1). The deposit is thin, however, and much of the hill you are now ascending is underlain by bedrock.

2:  View of flat plain | back to map
Continue along the lane from Site 1, heading towards Breinton About a kilometre beyond site 1, as you start to descend over the top of the hill, pull in on the right at site 2 (picture above) at the entrance to the track to Upper Hill Farm.

Smooth plain and upstanding hills
View north-north-west from site 2.
Upstanding bedrock hills contrast with the smooth flat glacial plain in the foreground.

3: View of Hay Bluff | back to map
Site 3 is located 1.5 km beyond Site 2.
Pause at the roadside to admire the view on the left across the Wye Valley towards Hay Bluff.

Hay Bluff
View towards Hay Bluff at site 3.
Hay Bluff, lay above the glaciers that invaded the lowlands in the last Ice Age, but its rocky surface would have been fractured by ice.

4: Pause here | back to map
Two hundred metres beyond site 3, fork left to Breinton Common. After about 600 metres, the road runs along a steep hillside formed by erosion by the River Wye after the Ice Age. Pause at the gate on the left (Site 4).

View SW from roadside
View south-west from the roadside at site 4. The cliff you can see is in Tuck Wood and is on the far side of the River Wye and forms part of the Breinton gorge which was cut after the last Ice Age.
Continue along the lane into the village of Breinton Common and site 5.

How the landscape has changed

1 Around 25,000 to 20,000 years ago ice advanced over the landscape. In the area of the cross-section the land had an altitude of 80-115m, dropping further north to 50 m in the proto-Wye valley.

2 Till was deposited under the ice.

3 Locally, meltwater cut channels eroding away the till and cutting into bedrock north of Breinton Common (locations B6 and B7 on Breinton walk). There were still permafrost conditions: freezing and thawing caused sediment slurries to move down slopes.

4 A major channel (the River Wye) was then established when the glacier was still close to Breinton Common, cutting down (incising) to 52 m altitude, and forming the Breinton gorge. Terrace sediments then accumulated from meltwater as the ice retreated, building the floodplain up to 60 m altitude.

5 After the Ice Age, the supply of sediment diminished and the Wye incised to 48 m altitude.

6 Sea level rose causing the gradient of the rivers to get smaller and sediment to be accumulated building the floodplain up to around 52m altitude during the last 10,000 years or so.

5: Breinton Common village | back to map
From site 4 the road descends to the level of the Wye terrace then ascends to the top of the river cliff.
The noticeboard at site 5 shows some details of local walks. You can download a Breinton walking trail in the IceAgePonds app.

LIDAR hillshaded image Breinton Gorge
The following diagrams explain the possible sequence of events that led to the formation of the Breinton Gorge.

proto-Wye
Before the last Ice Age, a river known as the proto-Wye, flowed east to Hereford, passing to the north of a ridge of bedrock.

Ice advance
The sediments of the proto-Wye river were covered in glacial till deposits when the ice advanced from the west.

Ice retreat
Later the ice retreated to the west of the Brockhall quarry.

Second ice advance
The ice then advanced for a second time to make a ridge of moraine near to Brockhall Quarry which blocked the flow of meltwater.

Meltwater escape
With the proto-Wye route blocked, trapped meltwater cut new channels, some cut by meltwater under pressure beneath the ice, as seen for example at locations B6 and B7 on the Breinton Walk, where the water must have flowed uphill to the east.

There was also probably a stream on top of the ice in the position where the Breinton Gorge now exists.

Breinton Gorge cut
The stream on top of the ice was very powerful and as the glacier retreated further, the stream eroded through bedrock to create the Breinton Gorge of the modern River Wye 3 km (2 miles) south of the valley of the earlier proto-Wye valley.

Meltwater channel
The pronounced gully in the field is caused by erosion by glacial meltwater late in the last Ice Age
This is site B6 on the Breinton Walk.

Dry valley
Dry valley identified by the British Geological Survey as a channel eroded by glacial meltwater.
Meltwater channels can form in different ways, but this one formed under the glacier.
This dry valley can be visited as Site B7 on the Breinton Walk.

Ways in which meltwater channels form
A: Glacial meltwater dammed by ice and moraines, spills over and excavates channels in the bedrock.
B: Channels cut by meltwater streams flowing from the front of a glacier.
C: Meltwater flowing under pressure beneath a glacier cutting channels in the surrounding material.

6: Edge of meltwater channel | back to map
From site 5, the road goes downhill to the River Wye, which has cut a small gorge here. The road then rises towards the north with a short steep gradient at the northern edge of the meltwater channel (site B7 on the Breinton walk).

LIDAR image
LIDAR image of the area of the meltwater channels.

Across the A438 to site 7
Continue along the lane until you meet the A438 – Hereford to Brecon road. At the main road, go right for 200 m then left for Stretton Sugwas. After 100 m there is a wide gated entrance with a pedestrian gate into the nature reserve.

If you would like a more secluded spot to leave your bike, visit the reserve via the entrance near point 9 on the map.

Stop point for site 9 | back to map
Stop in this lay-by on the A438. Carefully cross the road and walk a short distance and take the minor road off to the right.

7: Entrance to reserve and site 7 | back to map
There are some interesting ecological and geological features near here.
This site, along with site 8 is covered in detail in the Brockhall Walk that you can download into the IceAgePonds app and also review on this web site under Walks.

Newly established ponds
This site was once an extensive quarry extracting sand and gravel. There are newly established ponds like this one and a large lake that you can view at site 8. For a walking tour of this site download the Brockhall Nature Reserve trail into tyhe IceAgePonds app.

Ecology at Brockhall Quarry
The site is popular with bird-watchers with plenty of wildfowl and waders in passage. Nevertheless, the water bodies here are low in biodiversity as they have only been recently established. In 2010, Herefordshire Amphibian and Reptile team were funded to create three new small ponds to enlarge the breeding habitat for great crested newts and insects including dragonflies. These are near site 7. Take care as locally the ground can be very soft when waterlogged.

Glacially transported boulders
Glacially transported (erratic) boulders in foreground and shallow settling pond in background.

The pond is rich in aquatic invertebrates and arguably replicates some of the conditions following the glacial retreat. It is typical of a pond in the early/mid stages of succession and supports species of water beetle associated with kettle hole ponds. The pile of erratic boulders was placed by the ponds to encourage dragonflies to bask.

Site 8 access
The route follows a left turn to Barnfield farm after which it becomes a bridle way along the line of a Roman road west to Kenchester. There are two kissing gates along this route and you want the second one.

8: Brockhall Quarry Nature Reserve | back to map
The main lake in the landscaped Brockhall Quarry site, viewed from the north (site 8). There was a long history of quarrying sand and gravel here creating temporary geological exposure which revealed how the ice advanced and retreated in the last Ice Age.

Since the quarry was abandoned, new habitats are gradually becoming established.  See the Brockhall Walk for more information.

Sand and gravel extraction
Extraction of sand and gravel here was already happening by the 1880s and expanded in the 1930s and a wide area was covered by the 1970s. Quarry faces were up to 20 m high but there are none still present, the land being restored with lakes and seasonal pools.

This area represents a moraine where the glacial deposits are unusually thick, being deposited when the ice margin was at this location. The deposits include till, layered lake deposits and thick sands and gravels from meltwater streams and reveal a complex history of ice advance and retreat.\n\nStones lying on the surface today show characteristic shapes showing that they have been transported under ice. An added significance, as seen in the LIDAR image overlay, is that this moraine caused a blockage in what had previously been a valley of the proto-Wye. Hence, when the ice retreated, meltwater cut a new channel that became the Breinton gorge.

Moraine blocking proto-Wye
As can be seen in the LIDAR image, a moraine in the Brockhall Quarry area caused a blockage in what had previously been a valley of the proto-Wye. Hence, when the ice retreated, meltwater cut a new channel that became the Breinton gorge.

Glacial geology
The glacial geology exposed within Brockhall Quarry (historically referred to as the Stretton Sugwas pit) was spectacular and varied, changing decade by decade as the quarry expanded. No detailed research account is available in the public domain, but several different beds representing distinct events are recorded which together reveal the history. Details in the Brockhall Walk.

10: Pond in hummocky moraine | back to map
After reaching the Kenchester road, a short ride downhill to the north brings you to this point where you can view a large pond.\n\nThe Kenchester area is a classic one for showing a hummocky topography which represent moraines – piles of debris left by ice.

In hummocky moraine territory
You are now in hummocky moraine territory and there are many Ice Age ponds.
The pond you can see through the gate (“Pond 8” – see the following LIDAR image) is up to 150 metres wide, but contracts greatly seasonally. There is little emergent vegetation but it remains attractive to waders and wildfowl.

Kenchester ponds and deposits
The Kenchester ponds are regarded as classic kettle holes formed by infill of deep hollows created by ablation (melting and sublimation) of ice (see Ablation in Ice Words A-Z) .

The LIDAR image is of ponds in the Kenchester area with superimposed geology (British Geological Survey on-line data © UKRI [2020].) Many Ice Age ponds have an infill composed partly or mostly of peat, but this is often not shown within the area of this map. Each pond lies in a closed depression which means there is no stream draining out of them. Between the ponds are hummocks of glacial sediment.

11: Pull-in for site 11 | back to map
From Site 10, you reverse your route uphill to the hamlet of Kenchester, turning west to this pull-in by a pair of metal gates.
Site 11 gives you a chance to walk along a public right of way and see a closer view of an Ice Age pond.

Through field to visit pond 3
Walk through the field (muddy in wet weather) to the point where you can see a large pond. You can also take your bike if you wish.

Pond 3
Labelled  as ‘Pond 3’ in the earlier LIDAR image.
The water level in this pond varies greatly in different seasons and has flooded more in recent years.

Groundwater spring
A groundwater spring to the north of pond 3 connected by a shallow channel visible at low water level.  As water levels draw down and bare mud is exposed, a plant community of docks and nettles develops locally under these naturally eutrophic (nutrient-rich and oxygen-poor) conditions. Rare Docks such as Golden and Marsh Dock may grow from the seedbank.

12:  Viewing Pond 1 | back to map
Continue west on the road for 200 metres until you reach a small lay-by on the left just before a gate on the right (Site 12).
Over the gate you will see an intensively vegetated and wooded pond – Pond 1.

If you are doing the short version of the tour, you retrace your route to Hereford after this stop. A suggested return route to Hereford is marked on the map, or you could simply return along the same route used to reach site 12.

View of Pond 1 from gate
From the gate look to your right to see this unaltered kettle hole with reeds and pollarded willows.

Unaltered kettle hole pond
Photo of Court Farm and Pond 1 viewed from close to Site 12. Pond 1 is considered to be one of the most unaltered kettle hole ponds within the county.

Reeds and pollarded willows Pond 1
The zones of aquatic vegetation around the pond support nationally rare plants and a range of plants and animals confined to kettle hole ponds and so the pond has a natural look to it. This suggests that the pond has not been modified or managed to a great extent over the centuries.

Through Bishopstone to cross-roads
From site 12 continue west along the lane through Bishopstone to the cross-roads.
At Bishopstone a borehole here cited by the British Geological Survey proved over 24 metres thickness of sand and gravel.

Choice of routes | back to map
For the standard on-road route, to sites 13 and 14, also the return route direct to Hereford, turn right at these crossroads.

For an adventurous off-road route alternative route (which goes via site 13A rather than site 13 to site 14) you should 
download an additional .gpx file. The route goes go straight ahead for a short way on the lane, then take the track and fields round the northern tip of wooded Garnons Hill. Turn right when you emerge on a surfaced lane and then left down a rough bridleway to the site of Scuts Mill, along a drive and meet another surfaced lane at a T-junction; turn right, ascending along the crest of the moraine ridge with the Letton basin appearing to the left, to reach site 14. (This route is also marked on the map available in the app).

13A: Staunton moraine from Garnons Hill | back to map
View to the west from the north side of Garnons Hill, which is based on bedrock. The Staunton moraine has a distinctive flat top.

Site 13A lies on the off-road cycle route.

13: View of Staunton moraine | back to map
The Staunton moraine viewed from the A480 near Upperton farm. The hills you can see in the far distance include Hay Bluff and were well above the glacier. The ridge in the middle ground is made of glacial deposits and is known as the Staunton moraine. As we will see, it impounded a lake during the retreat of the ice.

Route to site 14 | back to map
From the A480 turn left onto the B4230, continue on the B4230 for about 800 m, then turn right onto a lane. Continue along this lane to a junction where you turn right and finally travel along the top of the Staunton moraine to site 14.

14: Site 14 stop | back to map
Stop at this point to view the Staunton moraine.

Viewpoint
First look at the roadside boulder on the right, then you can take your cycle off the road and walk down the track as shown.

Ice scratched boulder
This boulder set into the verge on the east side of the road shows a shaped and scratched surface suggesting it has been transported by ice.

View point for moraine
View from track about 30 metres from the road.

Lake behind moraine
Sketch of the Herefordshire ice lobe soon after the formation of the Staunton moraine when a lake formed in the Letton Basin.

The Stauton moraine
Down the track from Site 14 there is a splendid view down from the Staunton moraine to the west into the Letton basin which is continuous with the Wye floodplain.
Although the moraine ridge is 30 m higher than the surrounding lowlands, geophysical surveys indicate there to be only 10 m of glacial sediment in most places. Hence, the glacial deposits were draped over a pre-existing bedrock ridge. However, this is not the whole story!

Present-day topography
LIDAR image showing the present-day topography, Wye floodplain, Letton basin, and inferred path of the proto-Wye river.

Although the Staunton moraine overlies a bedrock ridge to the east of the Letton Basin, the same is not true to the south. At Staunton-on-Wye (S), a borehole at 100m (i.e. 100 m above sea level), proved an exceptional thickness (50 m) of glacial deposits on bedrock. So, prior to glacial deposition, the landscape was only at 50 m above sea level, some 10 m lower than the Letton basin and the Wye floodplain is today. It can also be seen that the Wye has incised as it passes Oaker Hill as there are cliffs against its floodplain. We can therefore conclude that the former position of the Wye (the proto-Wye) lay in the Letton Basin flowing down past point S. This route became blocked by morainal deposits and when the glacier stagnated meltwater was trapped and a lake formed in the basin. Then, meltwater found a new route to the west of Oaker’s Hill, cutting through bedrock to do so. Such an interplay of moraines and lakes is known to be widespread along the eastern margin of the Welsh ice sheet from Cheshire southwards.

Panorama of Letton Basin
Panorama of the Letton basin from the track leading down from site 14. The basin is liable to flood spectacularly as it is on the same level as the Wye floodplain. Afterwards you can continue on part 2 of the tour by continuing north to Norton Canon with an option to follow the walking trail at the Sturts Nature Reserve in the Letton basin.

Letton floods
Aerial view looking east from the Wye floodplain across the Letton basin, taken in February 2020. A former course of the Wye lies to the left (north) of Oaker’s Hill, whereas its present course is to the right (south) of the A438.
[Letton floods aerial image Christopher Furlong – Getty; thanks to Lewis Goldwater for assistance with labelling.]

What next? | back to map
This has now completed part 1 of the Landscape Tour.  You can return to Hereford the same way or continue down to Norton Canon and then via the A480.

There is a lot more to see in the area when you are ready. The Letton Basin you viewed at site 14 is the location of a walking tour around the ice-age ponds of the Sturts Nature reserve.

Part 2 of the tour takes you across the eroded central part of the glacial terrain with deeply eroded valleys and then you pass into the hummocky moraines and ponds of the Arrow Valley in beautiful quiet countryside.