Six years ago, I compiled a small photobook “The Trace Fossil Stones of Gemstone Beach”. I constructed it online and it was printed by Diamond Photo. Unfortunately the company changed their server sometime along the way and I have been unable to reprint the book. I have now almost finished an expanded revised version, reconstructing the content and updating it along the way. This Post will be used to provide identification for some of the extra stones I have included from various South Island beaches in the last part of the book. This will be done over the next month or so.
Category: Trace Fossils
March 2026 Stone Collecting Trip – Part 6, Lots of Sand on Gemstone Beach, Tuesday 17 March
I am staying with Chrissy and Mike, and Ohla the dog, at Papatotara, a few kilometres west of Orepuki’s Gemstone Beach. Today, Chrissy and I spent three hours there, on a cloudy afternoon with a light breeze, the temperature being around 16 to 17 degrees. There were four vehicles in the carpark when we arrived, with two more arriving just after we got there. The beach in front of the carpark was predominantly sand, with just a couple of patches of stones on either side of The Stream With No Name (marked as “Un-named Stream” on the map below – see this Post for more on the beach and its location).
Gemstone Beach. Source of base map = mapcarta.com
A sandy Gemstone Beach, looking north west.
Looking back towards the carpark.
You can always spot stones in the Taunoa Stream. Today it was running low and was easily searched and then forded.
Chrissy looking at stones in the bed of the Taunoa Stream.
Looking up the Taunoa Stream towards a recent new house.
Normally, masses of stones appear on the beach not far on the other side of the Taunoa, as you walk along the Te Waewae Bay coast, but that was not the case today. We struck more and even more sand for a few hundred metres, with only tiny patches of stones along the base of the cliff backing the beach. The large area of stones didn’t start until maybe three hundred metres before the Waimeamea River – see the description of “Section Three” in this Post for more about this 1.5 kilometre stretch of beach. (I’ve included Chrissy in some photos to provide a sense of scale – thanks to her for agreeing to this.)
For a long stretch of the beach, only small patches of stones at the base of cliffs.
Chrissy at the “cut” in the cliffs, which has had up to a metre of sand washed into it.
Exposed stones appeared as we got closer to the Waimeamea River mouth.
We decided to turn back at the Waimeamea River mouth. I think we could have forded it if we wanted to go further, but our backpacks were getting heavy.
The usual masses of stones, close to the Waimemea River lagoon.
Chrissy making her way slowly along the beach.
The mouth of the Waimeamea River. Not too deep today.
Bank of stones on left, dry Waimeamea River lagoon full of driftwood to the right.
The beginning of the wet Waimeamea River lagoon area, the river mouth is centre left.
Chrissy in the distance, looking for stones at the Waimeamea River mouth.
Te Waewae Bay waves.
Te Waewae Bay coast beach stones.
Te Waewae Bay coast beach stones.
It turned out that our backpacks became quite heavy. It was hard going trudging across the metres and metres of sand back to the carpark. When we got there, we met Robyn Bennett and her friend Judy. Robyn had messaged me about a week ago, having read TumbleStone Blog as well as some of my posts in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. She had told me they would be coming to Gemstone Beach at the beginning of this week, so it was good that we were all there at the same time. We had a good chat and showed each other some of our finds, as rockhounds do.
This afternoon’s fossick featured trace fossil stones – I kept on coming across them, and some were very good specimens or unusual for some reason. They made up maybe one-third of the stones I put in my bag. And Chrissy always gives me good ones she comes across. We saw very few hydrogrossular garnets and I found only one tiny poppy jasper. But there are always interesting stones that crop up when time is spent along this part of the Te Waewae Bay coast. Fourteen of my finds are featured below.
First, the big and the tiny. This is the largest of the trace fossil stones I collected, with the longest trace I have seen for some time. And following it is a tiny poppy jasper fragment I found, which still looks amazing in close-up:
Long trace fossil in argillite.
Tiny fragment of poppy jasper, with hematite.
Green stones can often be found on this beach. Two green-coloured stones I picked up, one light hued, one dark:
Complex structure and intense green veins.
Other side of stone.
Brecciated, black veins.
Other side of stone.
A pink find, most likely a rhodonite, similar to one featured in an August 2025 fossick:
Probably rhodonite.
Other side of stone.
This next stone is very unusual, with a mineral of light cream colour set in translucent quartz(?). In addition, there is a smearing of dark brown iron oxide across it:
Interesting colours and structure.
Other side of stone.
Another unusual stone, of mottled black and dark red:
Unusual mottling in this stone.
A stone with fragments of different colours, maybe a breccia?
Breccia?
Finally, six more trace fossil in argillite stones I collected today, showing some of the diversity of this type of stone – variations in colour of stone, colour of trace, and shape and size of trace:
Trace fossil in argillite, the most common green colour of host stone..
Grey trace fossil stone.
Light grey stone, very light grey traces.
Many tiny trace fossils.
Black argillite stone.
Trace fossils in a banded argillite?
Gemstone Beach and nearby Te Waewae Bay coast never disappoints me. I’ve always found at least one unusual and interesting stone, usually many more. Even if, as today, I have to walk a ways to find them.
The next Post in this Series reports on another visit to Gemstone Beach, two days later. An Index to this Series is here.
U is for U-Shaped Trace Fossil Found Near Ure (Waima) River Mouth
This is a slight expansion and rearrangement of my letter “U” contribution to the current weekly Alphabetical Series in the Facebook Group “New Zealand Lapidary, Rocks, Minerals, Fossils”. In the 2021 version of this Series I posted “U is for Unusual Variations of Trace Fossil Stones”.
U is for U-Shaped Trace Fossil Found Near Ure (Waima) River Mouth
U-shaped trace fossil in limestone pebble from near Ure (Waima) River mouth.
I have struggled to find a stone starting with “U” so I’ve decided to go with one I found about four years ago just south of the Ure (Waima) River mouth (see Day 24 in this Post). With a little imagination, this stone has a U-shaped trace fossil in it.
Between Kaikoura and Ward on State Highway One, not long after crossing from Canterbury into Marlborough, you come to a bridge over a river marked as “Waima (Ure) River”. Marlborough Online states: “The Waima (literally meaning white water, due to the limestone in the river bed) or Ure River has its mouth a few kilometres south of Ward, and is the southernmost river fully within the current Marlborough District… For much of its length of about 30 kms, it flows through rugged limestone gorges… The European name Ure presumably derives from the Ure River in Yorkshire which also runs through limestone country.”
Location of Waima (Ure) River mouth, south of Ward. Area in red is where stone was found.
The beach just south of the Waima (Ure) River mouth.
A scattering of lighter-coloured limestone pebbles.
Along this coast, you can find many limestone pebbles that contain trace fossils – lines of dark-coloured burrows or trails through sediment that have been preserved in the light-coloured stones. I have collected a number of them with a wide range of trace shapes and sizes. Here are four more from the same beach:
Criss-crossing trace fossils in limestone.
A common pattern of trace fossils in this area.
Nearly a U-shape.
Trace fossil in limestone.
On page 64 of “A Photographic Guide to Fossils in NZ” by H. Campbell et al. (2013), it is noted that these trace fossils can be found in Muzzle Group geological strata in Marlborough, in fine-grained limestone, marl, mudstone and siltstone, laid down in deep water (over 150 metres), the traces due to burrowing activity by something like an echinoderm. An echinoderm is a marine invertebrate, like a starfish, sea urchin, or sea cucumber, that has a spiny skin and a five-part (or more) radial symmetry. Other marine animals leave traces as well.
From page 64 of “A Photographic Guide to Fossils in NZ” by H. Campbell et al. (2013).
Trace fossil in limestone in situ, on beach south of Waima (Ure) River mouth.
Kaikoura coast beach stones, near boundary of Canterbury and Marlborough.
These stones are too soft to tumble polish successfully but a short tumble in fine grit removes a thin outer layer, smooths the stone and clarifies the traces. It also often leaves a nice smooth waxy-feeling stone.
For more on this type of stone see “Selection of Tumbled Ward Beach Stones: Part 1 – Trace Fossils in Limestone”.
The next Post in this Series is “V is for Veined Vein?”. An Index for this Alphabetical Series is here.
TumbleStone Calendar 2026: July – Trace Fossils in Argillite
The Introduction to this Calendar can be found here.
July’s stones in the 2026 TumbleStone Calendar are five Gemstone Beach argillite pebbles with trace fossils in them. Locally they are often called fossil worm cast stones. Argillite is a sedimentary rock, a hardened slightly recrystallised mudstone. Along with greywacke, it comprises the basement rock of New Zealand. On Gemstone Beach, argillite stones are mainly green in colour but there are grey and red ones as well, with some banded argillites being brown. Examples of Gemstone Beach argillite stones can be found here. Trace fossils can be found in sedimentary rocks – they represent the movement and burrowing of animals across or through the sediments. A “trace” fossil is not a fossil of the animal itself but of something it has left behind. In the case of July’s trace fossils, the traces are a different colour than the surrounding rock because the burrows or trails have been infilled by different coloured and often finer-grained sediment. Some of the trace fossils in argillite on Gemstone Beach can be plain, short and straight but others can be sinuous and long, with lines of chevron shapes – this diversity can be seen in “The Tattooed Rock, The Trace Fossils… Revisiting Gemstone Beach’s Trace Fossil Stones”. The most interesting, to me, are the traces that fit into the protovirgularia grouping – see “Ichnogenus Protovirgularia and the Permian Rocks of the Eglinton Valley”.
Calendar Cover, 2026.
July.
July’s Argillite Stones with Trace Fossils.
Stone One (top row, left, in the Calendar) contains a number of trace fossils, the main one being a good example of a long sinuous protovirgularia trace made up of a number of chevron shapes:
Stone One, July.
The smaller roundish “spot” traces in the stone are likely to be end-on views of long traces – the burrow or trail is at right angles to the longer traces we see. I found Stone One on 25 March 2025 – it is a grey-green colour, not uncommon for trace fossil stones.
Stone Two (top row, right, in the Calendar) has a straighter protovirgularia trace in between two plainer ones which also have a hint of chevrons:
Stone Two, July.
Stone Two was found on 12 August 2025, and it is a lighter green than Stone One, again a common colour for Gemstone Beach’s trace fossil stones.
Stone Three (bottom row, left, in the Calendar) is a dark, almost black, argillite – the traces within it are a mix of black and light green, looking much like caterpillers crawling through it:
Stone Three, July.
I found Stone Three on 3 August 2025, the day I saw an aircraft land on the beach between Gemstone Beach and Monkey Island.
Unlike Stones One, Two and Three, Stone Four (bottom row, centre, in the Calendar) has a couple of trace fossils that are darker in colour than the surrounding rock:
Stone Five, July.
It looks like there are very tiny pieces of dark grit or fragments in the two central traces, giving them an unusual texture. I found a number of variations of trace fossil stones the day I found this one, on 21 August 2025.
Stone Five (bottom row, right, in the Calendar) is one of the more rare types, having red traces:
Stone Five, July.
Again, the trace belongs to the protovirgularia family. I found Stone Five on a bitterly cold day, on 27 September 2024, another good day for finding a variety of trace fossil stones on Gemstone Beach.
For August’s set of yellow stones, see this Post.
Finally Found! A Small Trace Fossil Stone from Kai Iwi Beach
Trace fossil stone.
Trace fossils in dark green argillite. They have eroded at a slower rate than the host argillite.
Stress fractured trace fossil.
Nice dark trace fossil.
One of my favourite types of stones to find at Gemstone Beach in Southland is the argillite that has trace fossils in it (see photos above). There are a few variations of them, with different coloured stones (green, red, black…) and different trace shapes (the most attractive to me being the lines of chevrons). There are lots of these stones there, and I have found them too at Riverton Aparima. See, for example, “Southern Sojourn 2023(18): The Tattooed Rock, The Trace Fossils… Revisiting Gemstone Beach’s Trace Fossil Stones, February 2023” and “U is for Unusual Variations of Trace Fossil Stones and V is for The Chevron Shape of Trace Fossils”.
I have become aware that trace fossils in argillite can also be found elsewhere in New Zealand. After I moved to Whanganui a few years ago, I was told that on rare occasions they could be found on nearby Castlecliff Beach, then my wife found a couple on South Beach when riding her horse there. Bruce Taylor, a keen fossil hunter, showed me a couple he had found on Kai Iwi Beach. These have all been green stones, the most common colour down south too. I have been keen to find one for myself. For a few weeks, I have been walking our dog early in the mornings on Kai Iwi Beach:
Jasper the dog waiting for me on the walk down to the beach. Down below is Archer’s Bridge across Kai Iwi Stream.
On the beach.
On a large lump of fallen mud. from the cliff.
A great beach for a dog to get some exercise.
During our walks, I constantly scan for stones to tumble polish. There are very few stones there, usually widely-scattered, and not many are colourful or interesting. Mainly iron-stained quartz can be found, which often tumble polish well – see “The Iron-Stained Stones of Kai-Iwi Beach” and “K is for Kai Iwi Beach Stone” . I always hope to come across an argillite with trace fossils but for a number of years, my hunt has been fruitless, without even a green argillite being spotted. Then last week I finally found a small green argillite with a trace fossil!
Small green argillite with trace fossil, Kai Iwi Beach.
Other side of stone.
It’s quite small and innocuous. The main trace fossils in it, probably burrows, are rather plain. There are hints of maybe other smaller traces, difficult to see. But to me, this is an outstanding find, long awaited.
The waves have rearranged quite a bit of sand on Kai Iwi Beach recently, mostly removing it along one particular stretch of a couple of hundred metres. As a result, there seems to have been an increase in the scattering of stones that appears along the wave’s edge. That’s where I found this small trace fossil stone, more than 500 metres north of Archer’s Bridge, the pedestrian bridge over the Kai Iwi Stream.
More stones scattered along the beach than usual.
This large log used to sit on sand.
I witnessed this large slip recently – photo taken just after it happened.
Whenever I am on any beach, I can’t help but scan for stones. For the next few weeks, I will be on Kai Iwi Beach each morning, walking the dog so, who knows, another one might turn up. Or not.
August 2025 Stone Collecting Trip – Part 13, Coldest Fossick on Gemstone Beach, Monday 18 August
The family that was on the beach when I arrived.
It’s been a few days since my last fossick at Gemstone Beach. On Friday and Saturday, I had visited a beach closer to where I was staying. On Sunday, it was cold and wet and windy so I stayed inside. I decided to be brave and venture out today. In the morning, it was cold and wet and windy but the weather forecast looked promising for the afternoon – I use a weather forecaster called “Yr.no” and it provides hour by hour forecasting that I generally find very useful. “Yr.no” is a popular, publicly-funded Norwegian weather service that provides surprisingly detailed weather forecasts worldwide through its website and mobile app.”Yr” means drizzle in Norwegian. The service is jointly produced by the Norwegian Broadcasting Corporation and the Norwegian Meteorological Institute.
“Yr” map for southern coast of South Island, New Zealand. Note: Wind is in metres/second.
“Yr” forecast page for Orepuki. Note: Wind is in metres/second.
“Yr” forecast for Orepuki today, hour by hour. Note: Wind is in metres/second.
I arrived at Gemstone Beach at 11.40am – it was an outgoing tide with low tide due at 2.00pm. The temperature was only six degrees, but at least the rain stopped when I arrived. Initially there was very little wind but halfway through my fossick, , a bitterly cold breeze sprung up, stinging any exposed skin. Despite the dark day, one carload of what was probably a Mum and Dad with a young child were there when I pulled up, and even more people arrived after that. The Taunoa Stream was running too high and fast to cross, due to the rain over the last day and a half, so I spent just over an hour fossicking back and forth a couple of times on the beach in front of carpark. The temperature had risen to nine degrees when I left at 1pm. I found one small but kind of different poppy jasper and only one small hydrogrossular garnet but a number of interesting looking stones.
Arriving at Gemstone Beach on a cold wet day just before noon.
The family that was on the beach when I arrived.
Others arrived while I was there.
The Taunoa Stream, too fast and deep to cross today.
My finds today.
Gemstone Beach stones near the Taunoa Stream.
Gemstone Beach stones near the Taunoa Stream.
Gemstone Beach stones near the Taunoa Stream.
The small poppy jasper I found today was interesting because the orbs were spaced apart, not crowded together as is more usual:
One side of the small poppy jasper.
Other side of the small poppy
An intense green stone with lots of little bits in it:
The purple hues and white shapes in this stone caught my eye:
I like the dark stones with white crystals or spots. In the first side of this stone, the regular white spots are interrupted, are smaller and fainter:
I have found lots and lots of breccia stones on Gemstone Beach, where the fragments (“clasts) in the stone are angular (see this Post from September last year, for example). Conglomerates contain rounded fragments, and I have been looking for specimens without success until maybe today. The larger fragments in this stone are rounded, although some the tiny fragments are angular:
Sometimes a stone may not be purely a breccia or conglomerate but may contain both angular and rounded clasts. I’ve been trying to think of a good name for such but have not yet thought up one.
A partly brecciated stone, with tiny angular fragments:
I picked up this trace fossil stone because of the way some of the traces seemed to radiate from a central point, an unusual pattern:
Normally I tend to collect protovirgularia traces – lines of chevrons – but there are a wide range of other types of traces. A well-illustrated account of the different types of trace fossils can be found in this Sedimentary Geology textbook.
I have yet to turn my mind to the range of types of traces in the Gemstone Beach stones.
Seven other of my finds today, a wide range of colours:
Yellow quartz.
Jasper quartz.
Type of breccia?
A form of argillite.
The next Post in this Series describes a visit to Bluecliffs Beach, further west on the coast of Te Waewae Bay. An Index to the Series is here.
Selection of Tumbled Ward Beach Stones: Part 1 – Trace Fossils in Limestone
Ward Beach trace fossil stone.
Ward Beach “ringed” stone.
Ward Beach limestone(?) with quartz vein.
Ward Beach stone.
Ward Beach, in front of the carpark.
Two or three times a year, I drive from home in Whanganui to the South Island to collect beach stones. After the Cook Strait ferry crossing, and then again on my way north, I usually stay overnight at the Flaxbourne Motels in Ward, Marlborough. Occasionally I am able to visit nearby Ward Beach for an hour or two as well. The Motel is operated by Ronnie and Ian, who have shown interest in the Ward Beach stones I have collected and have been supportive of my blog. Last time I saw them, I mentioned I would bring them a few polished Ward Beach stones on my next trip. This Series of Posts describes some of the stones I will be dropping off, grouping them into six broad types, partly with the process of tumble polishing in mind. This first Post described limestone pebbles with trace fossils in them. Part Two features a range of other kinds of limestone. Part Three deals with two groupings: veined stones, and stones with dendrites. In Part Four I look at stones containing a mix of both soft and hard material. Part Five is about hard stones which are, of course, the easiest to tumble polish.
Limestone pebbles are reasonably common on Ward Beach, and indeed along the Kaikoura coast, and many of them contain trace fossils. A trace fossil is not the fossilised remains of a dead organism. It is a track, burrow or other kind of mark that relates to an animal’s (or plant’s) behaviour. A trace fossil is the record of an animal’s moving, exploring, hiding, breathing, hunting, feeding, excreting, playing, fighting, dying, or resting. An introduction to a kind of trace fossil that can be found at Ward Beach is in the Post “W” is for “Ward Beach Zoophycos”. As noted there, A Photographic Guide to Fossils of New Zealand has an entry (p.64) on these trace fossils: “This form has nested, U-shaped curving linear traces in the plane of strata; in three dimensions, it appears as a large auger spiralling through the strata…Ward Beach is famous for its smooth trace fossil-bearing pebbles.” The traces are due to the burrowing activity of some organism and were likely made between 35 and 84 million years ago.
Ward Beach trace fossil in limestone.
Ward Beach has quite a few trace fossil stones scattered across it. Being limestone, they are often dull due to the weathering of their surface. But if you look at them wet, the trace fossils are clear – that is why I often walk on the beach along the edge of the waves. I collect beach stones and them tumble polish them to make them smooth and shiny. I pick up stones that have interesting colours, patterns and lines, and I often don’t know what kind of stone they are. I discovered a few years ago that limestone is too soft for the normal tumbling process (four stages using different grit and polish, taking up to six weeks or so), quickly wearing away in the tumbling barrel. However, after some recent experimenting, I realised that a short tumble of a handful of days in fine (400 size) grit, followed by a short soap tumble, would remove the cloudy surface and leave a nice smooth waxy-feeling stone. The waxy feel is unusual and distinctive. Tumbling doesn’t give such a stone a high polish, but its surface is permanently clear, showing the trace fossil well.
Here are a few of the Ward Beach trace fossil stones I am leaving with Ronnie and Ian. Some of them, like these five, have one, two or even three “standard” traces through them (most of these stones are between two and four centimetres long):
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Other stones have unusual trace shapes or sizes – six examples:
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Ward Beach trace fossil stone.
Other limestone pebbles have plainer dark markings, lacking “nested, U-shaped curving linear traces” – these may be other kinds of trace fossils or simply different, and darker, sediment layers:
Ward Beach limestone pebble.
Ward Beach limestone pebble.
Ward Beach limestone pebble.
The next Post in this Series features other limestone pebbles I have found on Ward Beach.