Beach Stones – Page 11

Slapton Sands, Part Five: Beach Stones in the Rough

In his 1954 book, “The Pebbles on the Beach”, Clarence Ellis has a chapter on “The Coastline of England and Wales”. There he writes (page 125):

In the middle of Start Bay is a bed of shingle that must not be missed. This is the extensive bar at Torcross that encloses the lagoon called Slapton Ley. There is one very unusual feature about it. Its pebbles do not come from the rocks of the Bay. Many of them are flints, yet there is no chalk or other flint-bearing rock near to Torcross. The other pebbles are quartz, including very small ones that are pear-shaped, and granite from Dartmoor.

The website of the Slapton Ley National Nature Reserve has some good information on the bar, its beach and its stones. This Reserve is managed by the Field Studies Council in partnership with the owners. Whitley Wildlife Conservation Trust, along with Natural England and South Hams District Council. Their website highlights the significance of “longshore drift” which is when waves hit the shore at an angle and will move stones and sediment in a certain direction along a stretch of coastline. The website continues: [Note: August 2019 – The website has recently been changed and no longer contains this information]

Slate is the bedrock of Start Bay and so is found in the cliffs bordering the beach. It is a metamorphic rock, changed from clays by heat and pressure, but is relatively soft and so erodes easily. You may find large pieces of slate near the cliffs that have recently been eroded but because it breaks down quickly it is hard to spot much slate on the centre of the ridge. Schist is a very resistant metamorphic rock, and forms Start Point headland jutting out to sea at the south end of Start Bay. It was formed in the Devonian around 395 million years ago. The schist and some of the slate has seams of quartz running through it. Quartz is the most abundant mineral in the Earth’s crust and you will be able to find plenty of it on the ridge. It is a milky white. You can find some igneous rock on the beach, most transported by rivers that have their source on Dartmoor. Quartzite is pinkish and forms a very smooth pebble. It can be found just offshore and was transported up onto the beach by rising sea levels. Most of the shingle making up the ridge is flint; it makes up about 80% of the material on the beach. Flint is only found about 30-40km offshore from the present day coastline which suggests that Slapton Sands originates from this area.

During the visit to Slapton Sands in mid-2016, a few handfuls of stones were collected (59 individual stones in all). Some jasper and quartz are apparent. The photos below are of dry stones followed by some photos of them wet, hinting at how they might look when polished.

Slapton Sands, Part Two: The Protective Significance of the Shingle Beach

The shingle bar that makes up Slapton Sands, across which the A379 runs, and which protects the freshwater body of Slapton Ley, was deposited about 5,000 years ago. Further deposition has not happened since – any part of the coast washed away is not replaced by natural processes. Recent visitors will see significant signs of erosion along this part of the coast. For example, the beach car park, not far from Slapton village, is clearly being eaten away by the waves when the sea is rougher. Here is a view of the carpark in 2014 from Google Maps streetview, where erosion is not apparent. The following YouTube clips show the effects of a great storm early in 2014, including erosion along the beach:

A year later, 27,000 tonnes of shingle, deposited as a coastal defence measure, were washed away in one day, only three weeks after being put in place:

Just two or three kilometres to the south of Slapton Sands, at Hallsands, most of the shingle beach was removed in the late 1890s as building material for Devonport dockyards, leaving the village exposed to storms. It was struck by a storm in 1917 and most of the village was washed away. A local historian tells the tale of Hallsands in the following way:

In 1917 a huge bank of shingle was removed from about two miles off Hallsands, just south of Torcross, to help in the construction of a new breakwater at Plymouth harbour. W hen the next gale came, this vacuum filled with a gigantic wave which swept wildly inshore , up the beach, and completely engulfed the little fishing village of about twenty cottages. Even those cottages which were built higher up in the cliffs were affected, but happily no lives were lost. The vilage was never inhabited again, save by one occupant, the daughter of a fisherman. She had been born in the cottage, up on the cliff, which had always been her home, and soon after the disaster she returned to live alone, the only occupant of this ghost village. There she stayed until her death in 1970. (Grace Bradbeer, 1973, “The Land Changed its Face; The Evacuation of the South Hams 1943-44”, page 30.)

The view of Hallsands on Google Maps today shows houses atop cliffs – the original village was at the foot of these cliffs. Will Torcross be spared the same fate? The following YouTube clip from a “Britain is Great” TV programme tells the story of the importance of the shingle beaches of South Devon:

Slapton Sands, Part One: A Visit, Mid-2016

In mid-2016 a visit was made to some beaches on the south coast of England. One of these beaches was Slapton Sands, about 45 kms east of Plymouth. Driving through the village of Slapton, you come out to the coast just north of Slapton Ley, the largest natural freshwater lake in south-west England, being 2.4 kms (1.5 miles) long. The Ley is separated from the ocean by a bar of shingle, known as the Slapton Line, with Slapton Sands being the 4.8 kms (3 miles) long shingle beach on the ocean side.

The pebble beach at Slapton Sands, near the village of Slapton

On the Slapton Sands pebble bar

Slapton Sands pebbles

The gentle waves on a still afternoon, Slapton Sands

Slapton Sands pebbles

Below are two views northwards of Slapton Sands from the village of Torcross, just a couple of kilometres south of where the above photos were taken. The first photo was taken in 2012 and is from the Flickr account of Mark Coleman, with the second photo being from the “Essentially England” website page on Slapton Sands:

A two minute YouTube clip of Slapton Ley, Slapton Sands and its local region, mainly from an aerial drone, produced by the Field Studies Council. It includes views of the Field Studies Council’s Slapton Ley field centre, the Start Bay field centre, and Slapton Ley Nature Reserve.

A two minute YouTube clip posted in 2016 by Cornwall and Devon TV, on Slapton Sands for tourists – very beautiful.

A six minute YouTube clip of a person’s visit to Slapton Sands in 2011, showing Slapton Ley and its birdlife, the beach, and surrounding features.

The history of the Slapton Ley and Sands area is presented on the website of the Slapton Line Partnership, going back 100,000 years – click on the small circles under the timeline.

Another Visit to Birdlings Flat, Late June 2016 – Part Three: Seven Types of Stones Collected

During the six to seven hours spent at Birdlings Flat and nearby beaches during two and a half days at the end of June, I collected just over eight kilograms of stones. These consisted of a number of different types of stones. After my two previous visits, I had a good idea of what I was looking for, based on the results of some tumble polishing as well as my own preferences. There are many greywacke stones on the beach, the common grey beach stones of New Zealand, as well as a wide range of other types.

Following are listed the seven types of stones I collected during this visit:

Yellow-patterned Quartzite; Red Jasper; Agates; Green (Quartzite?); Patterned; White Quartz and Other Light-Coloured; Others.

Yellow-patterned Quartzite – This can easily be found at Birdlings Flat and is perhaps my favourite stone from there. I discovered a small boulder of it, that filled both my hands – which I had to leave at the beach. I have brought home at least two hand-sized specimens. There are a number of subtle colour variations of this stone, the best seeming to be a clear to light coloured quartzite with curtains or swirls of “gold foil” throughout it. The intensity of the gold/yellow can vary from stone to stone as can the patterns inside it. During this trip, I sought to collect stones exhibiting these variations.

Dry stones, as collected in late June

The same stones, wet

An idea of size

Collected earlier, smaller and with brighter yellow through it

Collected earlier

Collected previously from Birdlings Flat – swirls of gold through the clear silica

Collected earlier

Red Jasper – Red jasper stones can often be found on South Island beaches. They are reasonably easy to find at Birdlings Flat, where they can be of good size and quality. Many jasper stones have silica veins, sometimes bright red veins as well, and some other mineral staining can be present. They can be brittle, with chips and pits, making them difficult to smooth and polish.

Dry stones, probably jasper, collected from Birdlings Flat in late June

The same stones, wet

Collected at Birdlings Flat at an earlier date

Collected earlier

Agates – Birdlings Flat is well-known for its agates. A wide range of sizes, shapes and types can be found. It took me a while before I learned to spot them. The best way is to look towards the sun and your eye will be drawn to the light shining through them, even amidst a whole mass of other types of stones. On this trip, I found my largest agate so far, and a very small one with a green staining.

The agates collected at Birdlings Flat, late June, in their dry state

The same agates, wet

A sense of their size

Anagate collected at Birdlings Flat at an earlier date

Moss agate, from Birdlings Flat, collected earlier

Coloured agate, Birdlings Flat, collected earlier

Green (Quartzite?) – One of the interesting types of stones to be found at Birdlings Flat is green and I suspect is a type of quartzite. Again, there is a great diversity of them, from pale green through to lime green through to darker greens. I find them quite attractive and relatively easy to spot.

Dry green stones

The same green stones, wet

Patterned – I find myself drawn to even greywacke stones and other grey (or common coloured) stones if they have veins of white quartz through them or if they display layer patterns.

Dry

Wet

White Quartz and Other Light-Coloured – Going through the stones I collected, I find there are a number of white quartz stones and other white or light-coloured stones. These tend to catch my eye on any beach, standing out from the sand or the predominant grey of the most common stones on South Island beaches. I have learned to be more restrained in my collection of white quartz as it is easy to spot it and can soon mount up in the collection bag.

Dry

Wet

Others – What’s left in my collection bag after the rest have been taken away:

Pink stones are rare but present at Birdlings Flat. Some of these stones include ones of volcanic origin, characterised by small white pits

The same stones, wet

Dry, and…

…wet

Another Visit to Birdlings Flat, Late June 2016 – Part One: Taumutu

I introduced my wife Petra to Birdlings Flat. We started with a visit to Taumutu, at the southwest end of Kaitorete Spit (although Kaitorete Barrier Beach is a more accurate term for this enormous 25 kilometres long gravel bank). Taumutu is a rural district on the coast, the other end of Lake Ellesmere from the Birdlings Flat village.

The late winter’s afternoon was cold and windy so we had to wrap up warmly when we ventured onto the beach. We spent maybe only 30 to 40 minutes there before needing to retreat to the car to escape the chilling of the onshore wind. We managed to walk up and down the beach in both directions and collect a few stones. These were similar to those found anywhere along this stretch of coastline, including quartzites and agates.

We crossed this bridge to get to the beach – it had been undermined by a recent flood

Looking southwest upon arriving at the beach

Looking eastwards out to sea

Taking a photo of Petra taking a photo – looking northeast back towards Banks Peninsula and Birdlings Flat

A beach full of stones, the largest above the high tide mark, the smallest closer to the surfline

Taumutu Beach stones

A digger working on a trench to the sea to lower the level of Lake Ellesmere

Just across the road from where we parked the car

White Quartz Stone-Collecting at Hokitika

Yesterday I visited a beach just south of the Hokitika River mouth on the West Coast of the South Island. It was raining and cold, a south-west wind blowing in over the sea. This is a beach where the sea is advancing, where the land is being eaten away when the tides are high and the weather stormy. Access is by a road that heads towards the local golf course – a vehicle-track then turns off just past the bridge over the Mahinapua Creek. The track ends abruptly at the coast – the stretch that runs parallel to the sea is being washed away.

I walked along the beach, finding plenty of stones scattered across the sand, amongst the driftwood and remnants of flax roots. There are places where drifts of stones stretch down into the surf. The owner of the Annabelle Motel, where I was staying in Hokitika, told me this is one of the beaches where the people who make stone mats collect their raw materials.

The outstanding stone on this beach is white quartz. This type of stone is common in many places in the South Island and I found many varieties of it here. Some seem banded, some have inclusions of colour, some are pure white.

Looking northwards to Hokitika

Looking up the Mahinapua Creek

The Mahinapua Creek joining the Hokitika River right at its mouth

Drifts of stones being left by the receding waves

“A Stepping Stone…”

Stones from Birdlings Flat, in the polishing process…

“Windstar Aotearoa” by John Grenell

Windstar Aotearoa
Land of the long white cloud
Windstar Aotearoa
Let’s teach our children proud

We need to do more with what we have
And we can be more with who we are
And to feel the wind blowing upon our souls
And to reach out and touch a star

Windstar Aotearoa
Go forth and let your spirit free
Windstar Aotearoa
Held build a world of love for you or me

Hey let’s live a dream of being whole again
And fly with the hawks and touch the clouds
With spirit’s music played on instruments of nature
To live in harmony and he oh so proud

We can believe in hope, hey let’s believe in our dreams
You see, the rose you hold becomes a means
Each of us will build before our time has flown
A stumbling block or a stepping stone

Windstar Aotearoa
Land of the long white cloud
Windstar Aotearoa
Land of the long white cloud

“Beach Stones” by Josie Iselin and Margaret Carruthers (2006)

This is a book celebrating the beach stone in its raw form. Josie Iselin is a photographer and installation artist from San Francisco. She has published seven books which focus on those forms in nature that can be found “at hand” and, in particular, at the beach. She explains in the “Artist’s Note” on page 139 of “Beach Stones”, about ten years previously she abandoned her camera and instead started to use her flatbed scanner to gain a different level of detail in her images. All the pictures of stones in this book are scanned. Margaret Carruthers is an Earth Science writer from Baltimore and confesses to having “a vast collection of rocks” (dust jacket). Among her other books is the co-authored”National Audubon Society First Field Guide to Rocks and Minerals” (2005).

“Beach Stones” is a reflective rather than an investigative work. Stones are objects of intrigue and contemplation. The book collects stones from around the world, including a pair from Greymouth in New Zealand. One review expressed disappointment with the book in that there was not enough information of each stone. But that is not its aim. Its aim is more to get the reader to “really look” at the stones, as Josie has done, and to speak of them in a way that arouses curiosity and leads to further personal engagement with beach stones.

Physically, the book is 18 cm by 18 cm, consisting of 144 pages. Pictures of stones make up just over half of the book, and many of the pages of text contain just a few lines – the images of beach stones are its preoccupation. It is not expensive (Fishpond.com in New Zealand has it for sale at just under NZ$30). Every now and again, I enjoy spending time with a stone or three from its pages.

Birdlings Flat Stones After First Stage of Polishing

These stones have spent one week in a tumbling barrel with 100-mesh silicon carbide grit. This first stage of the tumble-polish process removes the weathered outer layer of the stone and brings out its colours more clearly. Many of these stones will be quartzites.

Just out of the barrel and having the slurry washed off – plastic pellets also present, used to provide some cushioning to minimise the stones striking one another

Drying before being examined individually to decide what happens next to each stone

My Visit to Birdlings Flat, Day 2: Stone Collecting

I bought some stones from Vince Burke at the Gemstones and Fossil Museum. I normally only like to collect what I find but there are special exceptions – and the Museum is a special place. Vince threw in some extras as well, so I came away with two rock agates from the Woolshed Creek area near Mt Somers, three large agate stones from Birdlings Flat, and some petrified and agatised wood from the Hororata River area.

But my main purpose that day was to find stones of my own that I could polish. So after I had visited the Gemstone and Fossil Museum, I spent about 2 1/2 hours on the beach, concentrating my time on the northern end, walking all the way to the cliffs. The wind was much stronger, but down near the waves was the lowest part of the beach and somewhat sheltered from the north-wester. There were slightly more people around this day than the previous one – mainly fishing and, like me, hunting for stones.

I chatted with three people. Charles came from Christchurch and had been interested in stone collecting for just a couple of months – he had a friend who polished stones but did not himself have a tumbler. Charles was nearing retirement age, like myself. He explained to me that he was mainly looking for agate stones – he gave me some he had found. I had not developed the eye to find them as they are rather plain looking and I tend to seek out colour. As we talked, Charles said, “Oh look, there’s one!” and he stepped a metre away to pick up a small agate. And a minute later, he spotted another one not far away.

Walking eastwards along the beach at Birdlings Flat

A fisherman ahead, and then Charles, who gave me some of the agates he had just found

I reached the cliffs at the end of the beach but did not linger long under them.

That night, I washed and inspected the stones I had collected.

Some of Day Two’s stones.

The agate stones I took away with me, most of them given to me by people I met on the beach.

The Museum stones. At the top is a rock agate from the Woolshed Creek area of Mt Somers; there is another one of these at right centre. At left centre are three large agate stones from Birdlings Flat. At the bottom, closest to the camera, is some petrified wood (left) and some dark agatised wood (right), from the Hororata River area.

Later I ran into a woman who I found out was the daughter of Vince Burke, the Museum man. She was also out looking for agates and generously gave me a handful. Later still, I encountered a local on his afternoon walk who told me a bit about the beach and its dangers. “It’s a killer beach”, he said. The waves can be treacherous, coming in further and more quickly than one anticipates – turn your back on them to your peril. And it gets deep quickly off shore – people who go in after their dog can get into trouble. He also gave me a few agates he had collected that afternoon.

I reached the cliffs at the north end of the beach but did not linger there. Charles had explained that one of the Christchurch area earthquakes had brought down part of the cliff-face. I had experienced a small but distinctly-felt earth tremor the night before in Christchurch and I was uneasy to focus too long on the stones at my feet when a mass of over-hanging cliff loomed above.

I collected somewhere between five and six kilograms of stones that day, to add to the eight kilograms from Day One. That evening I packed them carefully into both my cabin baggage and checked baggage for my flight the next day back to Hamilton. Heavy bags!