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WALK 1

Girvan and Grey Hill

Start/Finish	Girvan, south end (NX 183 964)
Distance	21km (13 miles)
Ascent	750m (2500ft)
Approx time	6½hrs
Terrain	Grassy hills, track, foreshore (rugged in places)
Max altitude	Grey Hill, 297m
Maps	Landranger 76 (Girvan); Explorer 317 (Ballantrae)
Public transport	Girvan station. Bus 54 (Girvan–Stranraer) stops at Lendalfoot to allow a linear walk.
Parking	Free car park with toilets and snack shack

Walkers spend the morning high up, for the sea views; the afternoon along the coast path, for poking in the rock pools. Grey Hill is a perfect little ridgeline – grassy to walk, with outcrops of odd lumpy rock for decoration. Lurid gorse clashes with a vibrant blue sky. At the trig point, peculiar pink stones form a grassy nook to gaze out at the island of Ailsa Craig.

Ailsa Craig is the plug of a volcano that popped up at the opening of the Atlantic a mere 50 million years ago. As ancient rocks go, that’s the day before yesterday. The pink rocks on Grey Hill are nearly ten times as ancient, and a whole lot odder. It’s a defective granite called Trondhjemite, which properly belongs below the ocean bed.

The coastal path weaves between former sea stacks of a raised beach, then heads north on a grass track – and on Lendalfoot foreshore are some really odd rocks. The final 3km are harder going, along beaches of sand and pebbles.

Head inland along the A77 to a roundabout with a red sandstone centrepiece claiming Girvan as Home of Ailsa Craig. Old Red Sandstone here and at the car park indicates that Girvan itself stands just north of the Southern Upland fault. Go straight across into a housing estate. As the street bends left, keep ahead through a gate signed ‘Girvan Barr hill path’. This track leads up past Piedmont house, over a railway, and through a bluebell wood.

At the wood top is a small quarry. Here turn right, up open grassy slopes. Cross an ancient field system onto the hill fort summit of Dow Hill.

The rock outcrops are a puddingstone (the Benan Conglomerate), containing large rounded cobbles. The basic grey is a greywacke-type sandstone, as found all across the Southern Uplands. The pink lumps within it are an alien rock, Trondhjemite, described below.

Head down southwest over an awkward fence (down right 100 metres to a field corner may help). Pass down to the right of a gorse grove to a gate and arch under the railway. A tractor track leads down to the A714. Cross and turn left along the pavement to a cemetery.

Turn right, forking left on a farm track. An earth track leads through Brochnell farm. (One or two walkers have reported trouble passing through Brochnell, with waymarkers removed. An alternative is to fork right rather than left after the cemetery, and make a way through a caravan site and the auto salvage yard above it onto the base of the hill.)

The track bears right to cross Bynehill Burn. Turn to the right up rough grassland to a gate. At the smooth track above, turn left for 30 metres to a waymarked kissing gate onto Byne Hill.

A small path leads up Byne Hill, over outcrops of the same Benan Conglomerate. At the ridge top, the small path continues southwest to the summit of Byne Hill.

The outcrops here are of pure Trondhjemite. It’s a pink and crystalline granite, but without granite’s back speckles. When exposed in outcrops it weathers to a dull grey – you’ll see clean chunks of it along the foreshore at the walk’s end.

Up the north ridge of Grey Hill, with Byne Hill seen behind

The small path continues down southwest to a stile. Head down through a wall gate to cross a col. A stone monument, decomposed so that whatever it commemorates has fallen off, is over on the right. Ahead is a slightly rocky hummock (Mains Hill), made of massive greywacke. Cross its grassy top and continue on down through low gorse to cross a stream. Go through fallen stone sheepfolds to a gate, with a faint grass track beyond. This runs up to the right of the stream, then leads up all the way to the trig point on Grey Hill.

Continue southwest along the small ridge path. The level summit section ends with a bit more Trondhjemite. Cross a fence on the way down to a col, with a gate in a wall, and go up the slight rise of Pinbain Hill. Keep ahead down the southwest spur of Pinbain Hill through a gate in a fence to a gate and kissing gate, where a gravel track contours in from the right. There is now a choice – to turn sharp right immediately, or to continue down the Ayrshire Coast Path ahead to a beach for a lunch stop before returning to this point. Turning back here saves 2km (¾hr).

Ahead are raised beaches along the shoreline to Lendalfoot, with former sea stacks projecting from the (now grassy) meadows behind the main road. The old beach, now above sea level, shows how the west of Scotland has been rising steadily since the weight of the Ice Age melted off.

To continue on the Coast Path take the grass track ahead through the gate. It bends right, down through what appears to be a quarry (actually a former sea cove with sea stacks). Cross the A77 and turn left along the pavement for 700 metres to a lay-by, above a cluster of beach rocks projecting seawards – Bonney’s Dyke.

SERPENTINE

Serpentine from Bonney’s Dyke

Just occasionally it happens that the crunching together of continents brings rocks from below the deep ocean floor right up to the surface. This has happened at two places in the UK – the Lizard in Cornwall and the Ayrshire coast between Girvan and Ballantrae.

One of the strange stones exposed is the pink Trondhjemite of Byne Hill. This is a primordial rock of the oceanic crust, formed at the mid-ocean ridge as the ocean on either side moved outwards. That rock is usually basalt, but can sometimes be Trondhjemite.

At Bonney’s Dyke, the turning point of this walk, appears a stone from even further down. It’s a gabbro, but with gabbro’s usual black crystals separated by a groundmass of off-white feldspar. This rock originally crystallised below the ocean floor. On the beach at Bonney’s Dyke are occasional dark, streaked pebbles, coloured greenish, reddish or yellow and slippery to the touch. This comes from even lower still. It’s the stone called serpentine (strictly, serpentinite), which is not from the earth’s crust at all but is from the next layer down, the mantle, 10km or more below the ocean floor.

The serpentinite rock forms cliffs at Balcreuchan Port, 5km south down the coast. It overhangs a cave once lurked in by the cannibal family of Sawney Bean.

Bonney’s Dyke to Pinbain Hill – the foreground rocks are speckled gabbro

Return alongside the A77 and up the grassy track. Once through the second gate, the track continues gravel surfaced, contouring below a mobile phone mast. The track crosses the steep hillside to Kilranny ruin. Here a kissing gate on the left lets walkers bypass the former farmyard and rejoin the track through another kissing gate beyond.

The track now runs gently downhill to sea level. Where it bends left across the green meadow of the raised beach (to the A77 just ahead), keep ahead (Ayrshire Coast Path waymark here, below strikingly folded greywacke rock). A rougher track passes along the inland edge of the raised beach. Just before Ardwell farm, turn down left to cross the A77 to a pathway signpost.

Follow the road verge for 300 metres, with folded greywacke rocks offering a very rugged alternative along the shoreline. As the road bends left it is possible to drop left onto the beach (unless the tide is fully in). Walk along the beach back to the walk start.