Guildford and Hogs Back Geowalk, Surrey
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GUILDFORD AND HOGS BACK GEOWALK, SURREY (embellished from a Geowalk established by Brian Harvey in April 2002) This circular walk is about 7 miles (11 kilometres) and looks at the relationship between geology, topography, land use, building stones, industry etc. This is a particularly beautiful and interesting area, and the geology will be suitable for any level of expertise from beginner to expert. There is a pub, the Harrow, about half way round at Compton. The walk starts and finishes at Mill Mead in Guildford town centre, located beside the River Wey and opposite the Yvonne Arnaud Theatre. Cars can be parked in the Mill Mead car park, map ref. SU 9950 4918 (44 spaces; free on Sundays only – 2011), or the nearby Portsmouth Road car park north of St Nicolas church (98 spaces; charges in 2011: Saturday £1.10/hour, Sunday £2.50 all day). Alternative parking is available in the Millbrook car park (from there walk down to the Yvonne Arnaud Theatre and cross the river by the footbridge). Mill Mead is within easy walking distance south of Guildford railway station. The route follows footpaths and tracks, some of which may be muddy, and there are a few hills to climb. Boots or walking shoes and a reasonable level of fitness are advisable. Starting in the Mill Mead car park, cross the (white) footbridge and then turn right to take the gravelled footpath that runs between the River Wey on the right and the Wey Navigation canal on the left. Stop 1 The canal lock on the Wey Navigation This canal was one of the earliest in the country, having joined Godalming to the Thames in 1653. It was later extended southwards to join the River Wey here to the River Arun, thus creating a canal link to the south coast at Portsmouth. As with all canals, it was used mainly for bulk cargoes over long distances. Amongst other things, it carried Bargate stone from quarries in the Godalming area (3½ miles south-west of here). Bargate stone has been used extensively in the local area, as we shall see, but it can also be found in London at places like the Tower of London. This Guildford section of the canal was closed in 1871 – killed by the development of the railway network, although more recently there has been a revival of interest and work is underway to reinstate the canal link. Continue walking south. After crossing a small weir, take the right-hand path immediately opposite Guildford Boathouse and continue along this path with the Wey Navigation on your left. Cross another weir and continue with the canal on your left. 1 Stop 2 Garden wall of Bargate stone (250 metres beyond the second weir) The stone used in this wall came from quarries near Godalming. Bargate stone is part of the Lower Greensand, and it is more-or-less restricted to Surrey (small areas do spill over into Hampshire and Sussex). It is a calcareous sandstone that was deposited as a marine delta in shallow water, because the 'south coast' of England at that time (120 million years ago) was slightly north of Guildford ! The stone in the wall here does show ooliths (they look like small ball bearings) and shells in places. Although the rock is relatively hard for this part of England, it weathers poorly because of the carbonate component, so the stone has to be replaced from time to time. Then after 75 metres (noticing the blocks of slag used in the footpath), you come to a steep narrow path on your right, alongside a small stream and bridge. The path is Ferry Lane. About 25 metres beyond the stream, and 25 metres before the footbridge that crosses the Wey Navigation, you can see a light brown outcrop in the wood up the slope to your right. Walk further south along the path and under the footbridge to a second, much larger outcrop 20 metres beyond the bridge, on your right. 2 Stop 3 Folkestone Sand This is our first view of the Folkestone Sand Formation. It is named after Folkestone, Kent, where the beds were described in detail. Compare this sand with the stone we saw earlier in the garden wall: this is definitely not rock (although the face can stand vertically !). It is friable and easily 'carved', as you can see. It has remained as a sand rather than become a rock because it lacks any cement between the grains, and so water can move through it much more easily (to produce springs). We can look at the Folkestone Sand more closely at the next stop. Here, we have a possible origin for the name 'Guildford', as the sand forms a 'golden ford' of lower ground at the river (or the canal, at this point). Walk back north under the footbridge and take the narrow steep path (Ferry Lane) off to the left just beyond stop 3. Walk up the hill and onto the railway bridge, then another 60 metres (beware occasional traffic). Stop 4 Grey stone wall on the left Compare these building stones to those that you have seen beside the Wey Navigation. They form a retaining wall for the slope, and are definitely not local materials. They are mainly 3 granite, and probably from Cornwall. Looking closely you can see the different crystals that make up this rock – they are black (known as mica), white (feldspar) and grey (quartz). At the junction with the main road (Portsmouth Road), turn right. After 50 metres, cross Portsmouth Road into Sandy Lane (i.e. 1st left), Continue along Sandy Lane, with Bradhoeuf Manor on your left. After 175 metres, take the driveway off to the right, way-marked North Downs Way. Follow this track for 800 metres, to (and beyond) Piccards Farm. Chalk FAULT U. Greensand Gault Clay Folkestone Sand Extract from Ordnance Survey map Licence number AL 100005035 = location (Ignore the track joining from the left, 140 metres before the farm). Pass through Piccard’s Farm and continue along the gently rising road for a further 400 metres. Then turn left (south) with the metalled road (at the notice marked ‘Private Please keep to footpath’). Continue straight on over the brow of the hill (the Folkestone Sand ridge), ignoring both the driveway on the right way-marked North Downs Way and then the public bridleway, until you reach the grassy triangle and hairpin road of Sandy Lane. Take the road straight on, now called Littleton Lane, down the hill past the toad sign (yes, toad) on the right. Walk on the right and beware traffic. Notice how the lane is sunken into the landscape, with high banks on each side. The ground is still Folkestone Sand, and over many centuries wheeled traffic on this route has worn it away (until the erosion was halted by laying a tarmac surface). 4 Stop 5 beside the sign for Littleton village (stand off the road). Here is a second small quarry on the right (you may also have seen the first on your way down Littleton Lane). Directly across the lane (east) is the boundary between the Folkestone Sand to the left, and the hard Bargate Stone forming a solid vertical face (admittedly concealed behind a covering of ivy) to the right. Unfortunately it doesn't photograph well. Continue downhill, and take the first turn to the right (west) just after Pillar Box Cottage, signed as a public footpath. Littleton Youth House will now be on your left. Continue straight on, through the kissing gate and follow the footpath across the grass. Cross the field boundary (no gate), and start across open ground (the field on the left was ploughed in 2011, showing a sandy soil as would be expected on the Hythe Formation, as well as ?chert). Continue on through another kissing gate next to the lake (crossing onto a strip of mown grass with a few seats). Continue west beside the lake and through the kissing gate at the far end, then keep the fence on your left. Far to the left is Loseley Hall, famous for ice cream, outdoor events and animal breeding. 5 Building work on the Hall started in the 1500s, and apart from a new wing added in the 1600s (but later removed), the Hall is outwardly unchanged. Much of the cream-coloured stone used for construction was re-used from an earlier building: the ruined Cistercian Abbey at Farnham which was ten miles away from the Hall. That makes sense because of the local lack of thick rock strata that can be quarried for stone, and for the cost saving on the shaping of the blocks. Another geological aspect of the Hall is that the towering white fireplace in the Drawing Room is made of 'clunch'. Clunch is a harder type of chalk that is obtained from specific levels within the Chalk mass; it is harder because it has a natural cement between the grains. Clunch was also used to build Guildford Castle. Once you reach the fenced track, turn left and after 280 metres cross the drive. Where the fence very soon turns sharply left (south) follow it round and up a very gentle rise to the driveway of Loseley Hall. Then immediately turn right (west) along this long straight drive/avenue (of trees), away from the Hall and car park. At a point 200 m beyond Polsted Lodge, the track bends right and drops, as Polsted Manor comes into view. Turn left at the junction, with the buildings of Little Polsted directly opposite (and where “Polsted Manor” is marked on the 1:25,000 map), and follow the metalled road downslope and right.