TumbleStone Calendar 2020

Happy New Year wishes to everyone!

In December I moved house from Cambridge to Whanganui. Everything was shifted by Christmas, and most of the unpacking has now been done.

However, the shed I will use for tumble polishing is still in the process of preparation.

Early in January, after the moving and unpacking, I quickly put together a calendar for 2020, using Diamond Photo online. For each month, the Calendar has a set of photos, just slightly smaller than an A4 page, with another A4 size page below it containing the month’s dates. The main internationally-recognised holidays are noted, along with some of the main New Zealand ones.

I was very pleased with the quality of the finished product.

If you want to buy one for yourself, email me at john.tumblestone@gmail.com. It will cost you $25 (postage included, in New Zealand).

The following are the sets of photos for each month in the Calendar – these are all photos I took in 2019, most but not all of which appeared on TumbleStone blog last year:
January – Riverton scenes
February – Close-ups of Gemstone Beach stones
March – Fossil worm casts in rocks at Tihaka Beach, near Riverton
April – Hydrogrossular garnets
May – Gemstone Beach scenes
June – Fossil worm cast stones
July – Larger stones found on Gemstone Beach and the beach near McCracken’s Rest
August – Polished stones from Gemstone Beach
September – Henderson Bay scenes, Riverton
October – Polished stones, collected by my sister Helen on Gemstone Beach
November – Close-ups of fossil worm cast traces
December – Polished stones, collected by Sam, my sister’s grandson, on Gemstone Beach.

“Here Is Where The Heart Is… Sea Winds Out On The Wild”

Out on the beach, in the wild wind and salt spray, the waves roaring in, the wet stones glistening in the winter sun – my Scottish ancestors must have known something like this…

Photos from the last three days spent by me on Gemstone Beach, finding many fossil worm cast stones, a lot of them too big for tumble polishing…

 

 

Wolfstone’s song (below) expresses Scottish ties to land, coast and sea, as well as their disruption and loss through the Clearances and emigration. Runrig’s song (further below) speaks of the modern Scottish recovery of identity and the struggle for more control over national direction.

“Here Is Where The Heart Is” by Wolfstone

Here is where the heart is, beats out like a drum
Here is where the Mavis* flies, where she once came from
Here is where the mother tongue resides,
Far from the hands of hate and greed and lies.

This is where my home is, the shore, the sea, the sand
This is where my family were raised from working hands
This is where the toil and sweat and tears
Knew only hardship through those working years.

From farm and croft and residence, they cleared them from the land
Families of young and old with one wave of a hand
Were sent on board to sail the ocean wide
To a stranger’s land o’er wind and sea and tide.

Here is where the heart lies, like those who’ve been before
Here there are no broken ties with brothers on the shore
Here is where the spirit will return
No more to sigh, no more to weep and mourn.

Here is where the heart is, beats out like a drum
Here is where the Mavis flies, where she once came from
Here is where the mother tongue resides,
Far from the hands of hate and greed and lies.

*”Mavis” = Song thrush.

Recovery” by Runrig

Watching the morning come in on the land
See the moon roll over Skeabost
See the young men late in the glen
All with camans* in hand

Sea winds out on the wild
Sea waves crash onto Uig
See the black homes strung out in a line
Across the island of Skye

I can’t believe
That it’s taking all this time
I can’t believe
My life and my destiny
After the clans, after the clearings
Here I am
Recovering

Should have been home before daylight
It’s not easy when you’re down and hungry
One from the late run rolled up in a coat
I make my way across the moor

For a late summer in ’84
But now there’s a new day dawning
I’ve heard the Braes men talk in Portree
The news from Glendale

And I can’t believe
That it’s taking all this time
I can’t believe
My life and my destiny
After the clans, after the clearings
Here I am
Recovering

Still the morning comes in on the land
See the new sun red and rising
See the corn turn ripe in the fields
See the growth in the glen

And MacPherson’s in Kilmuir tonight
What a night for a people rising
And oh God, not before time
There’s justice in our lives.

*”Camans” = The sticks used in the game of hurling.

The Fossilised Worm Cast Stones of Gemstone Beach and Riverton – Part Four: Ichnogenus Protovirgularia and the Permian Rocks of the Eglinton Valley

It can often be difficult for the non-expert like myself to identify a stone. Consulting books or the internet about different rock and mineral types can be frustrating because you can often find three or four possibilities that might match your stone. Moreover, your stone might have some characteristics that appear to be unique and not present in any of the “pure” types included in the books. There may be clues in how locals refer to a stone, though even they can be mistaken. You may be lucky enough to come across a reference to your stone by an expert somewhere, or you might even be fortunate enough to contact an expert who can help you.

This Post is part of a series on what are called “fossilised worm cast stones” found on Gemstone Beach and the beaches of Riverton in Southland. I have not come across any authoritative reference to them anywhere in the literature or online. Until now. Recently I received information on them from two different sources. This Post reports on the first source, and the next Post reports on the second. (The first Post in the Series can be found here.)

A FOSSIL TRAIL, ICHNOGENUS PROTOVIRGULARIA, POSSIBLY FROM NUCULA, A SMALL BIVALVE

In early July I emailed the following seven photos to someone I know in a University Department of Geology.

“The stones contain what are probably fossilised traces of worms”, I wrote. “I would like to identify the kind of rocks the stones come from, what kind of worm is involved, and when they were active (in other words, when did they start becoming fossilised).” My inquiry was passed on to another geologist with expertise in ichnology (the study of trace fossils) who replied: “Yes, a trail, probably ichnogenus Protovirgularia, usually attributed to a small bivalve such as Nucula. I’ve seen it in float boulders in the Eglinton and very similar pebbles on the East shore of Te Anau, where it is likely from the Permian.”

It seems to me that five points follow from this information:

1) The traces on the stones are trails . If this term is taken strictly and narrowly, then a “trail” is left behind on the surface of sediment by the movement of an animal. A “trail” is not a “burrow” nor a “cast” (excretion). However, a looser definition of a “trail” could include “burrow” and “cast”, so it is important to keep an open mind on this.

2) The trace is called ichnogenus Protovirgularia. My initial research into this term reveals the following. “Ichnogenus” is a category of taxonomy (a way of grouping similar things) for trace fossils. A “genus” is an intermediate category between “species” and “family”. In relation to the term “Protovirgularia”, “Virgularia” is a genus of sea pen in the family Virgulariidae (sea pens were discussed in Part Two in this series of Posts), and “Proto” means original, primitive, first or earliest. For a number of weeks I was not able to find out why this group of trace fossils was given the term “Protovirgularia” – I thought that maybe it was initially thought to have been made by a sea pen. It is reasonably well-established now that in the vast majority of cases the pattern is made by bivalves, though it can be made by other invertebrates (this may be the subject of a later Post). I was eventually able to find a copy online of the original article that first identified protovirgularia. It was written by Frederick McCoy (Professor of Geology and Mineralogy, Queen’s College, Belfast) in 1850 in the “Annals and Magazine of Natural History“. On page 272, McCoy wrote: “…In the form of its axis and the structure of the transversely ridged celluliferous pinnae, both in the curved extended, and in the straight contracted states, it perfectly resembles the recent Virgularia mirabilis…” (my underlining).

McCoy 1850 ab
Source: https://www.biodiversitylibrary.org/item/102950#page/302/mode/1up

In his 1850 article, McCoy also referred to Protovirgularia dichotoma which varied a little from the basic Protovirgularia he first described.

Below are photos of Virgularia mirabilis, also known as the slender sea-pen. The photo of a dead one on the far right below shows the resemblance noted by McCoy to the fossil he had observed, and he believed it to be of a primitive ancestor of this animal. It was not until 1958 that the fossil was identified as a trace fossil made by a different animal.

One academic source defines ichnogenus Protovirgularia as a small keel-like trail which is composed of an elevated median line and lateral wedge-shaped appendages alternating on both sides (see also the entry in FossilID). The following description of Protovirgularia dichotoma is very interesting in relation to the trace fossils found at Riverton and Gemstone Beach because of reference to chevrons (v-shaped patterns). This source describes Protovirgularia dichotoma trace fossils as “horizontal or subhorizontal cylindrical burrows, trapezoidal, almond-shaped, or triangular in cross-section, distinctly or indistinctly bilobated [having two lobes]. Internal structure, if preserved, is formed by successive pads of sediment that may be expressed as ribs on the exterior. Ribs arranged in chevron-shaped, biserial pattern along external or internal dorsal part.” Below are examples.

pv dich slide
Examples of Protovirgularia dichotoma from Spain. Source: https://www.slideshare.net/JordiMaria/bivalvia-2006-tt-compr

The photo below contains four examples of protovirgularia trace fossil specimens from Japan, discussed in a 2011 article in the academic journal “Palaeogeography, Palaeoclimatology, Palaeoecology”. The variations within the protovirgularia grouping is shown. Note too that these are three-dimensional traces in contrast to the trace in the Gemstone Beach and Riverton stones that have been subject to “flattening” by the smoothing action of the river and ocean.

????
Protovirgularia trace fossils from Japan. Source: Page 3 of https://www.academia.edu/849702/_Deep-sea_bivalvian_highways_An_ethological_interpretation_of_branched_Protovirgularia_of_the_Palaeogene_Muroto-Hanto_Group_southwestern_Japan

The diagram below is from a 2010 article on protovirgularia found in Patagonia, Argentina, published in the “Journal of Paleontology”. Again, the significant variety in the forms of this trace shape is demonstrated. Forms #3, #4 and #5 on the diagram look at first sight to be closest to the well-defined chevron shaped traces often found in the Gemstone Beach and Riverton stones.

carmona et al fig 4
Morphologic variations of Protovirgularia. Source: https://www.researchgate.net/publication/240776411_Taphonomy_and_Paleoecology_of_the_Bivalve_Trace_Fossil_Protovirgularia_in_Deltaic_Heterolithic_Facies_of_the_Miocene_Chenque_Formation_Patagonia_Argentina

3) Despite its name linking it to sea pens, it seems that this type of fossil trail, “ichnogenus Protovirgularia”, is usually thought to be left behind by a small bivalve. A “bivalve” is an aquatic mollusc which has a compressed body enclosed within a hinged shell, such as a clam, oyster, mussel, or scallop. Bivalves have inhabited the Earth for over 500 million years. They especially flourished in the Mesozoic and Cenozoic eras (the last 250 million years). The excellent British Geological Survey entry on bivalves as fossils shows how they are able to burrow into sediment. One article in the journal “Ichnos” in 2010, again on protovirgularia from Argentina, gives the following account of the link between the trace and bivalves: it is a locomotion trace produced by bivalves, a burrow resulting from the rhythmic action of a muscular cleft-foot (page 42). Nucula is a genus of very small saltwater clams, according to Wikipedia (see photo, below left, of Nucula in Te Papa Museum and, below right, Auckland Museum).

These clams are very ancient, having been around for the last 450 million years or so, and have been very common around the world. They can reach a size of up to 30 millimetres and  live in the muddy sand close to the sediment surface at an oceanic depth of 20 to 200 metres. It is thought that the movement of Nucula leaves behind the “ichnogenus Protovirgularia” trace shape. However, I assume there is also the possibility that maybe something else could leave that trace shape.

4) The trace fossil shapes found in the stones at Orepuki and Riverton have also been found on float boulders in the Eglinton River and in pebbles on the East shore of Lake Te Anau. The Eglinton River flows into Lake Te Anau at a middle point along the lake’s eastern shore, having made its way there from the north-north-east: 

A “float” rock is a loose piece of rock that is not connected to an outcrop, that is, it has been removed and transported from its place of origin, especially by gravity, ice, water or people. This often makes it difficult for a geologist to identify float rocks. In relation to the terms “boulders” and “pebbles”, when it comes to the sizes of float rocks, geologists use a set of categories. One such set is as follows: A “grain” (e.g., of sand) has a diameter of 2 to 4 millimetres, a “pebble” is between 2 and 64 millimetres, a “cobble” is 64 to 256 millimetres in diameter, and a “boulder” is larger than 256 millimetres. 

5) These trace fossils were likely laid down in the Permian period. The Permian spans 47 million years from the end of the Carboniferous period about 300 million years ago to the beginning of the Triassic period about 250 million years ago. The world at the time was dominated by two continents known as Pangaea and Siberia (the latter also known as Angaraland), surrounded by a global ocean called Panthalassa. The New Zealand area was on the southeast part of Pangaea and with it moved around the southern part of the globe, including over the South Pole area.

This is how a University of Waikato website, by the Biology and Earth Sciences Departments, describes the Permian context of New Zealand and some of its local geological happenings:

By Permian times, the continents were moving even closer together than during the Carboniferous as the northern and southern supercontinents of Laurasia and Gondwana began to assemble into a single great landmass, called Pangaea. The Permian period was the final period of the Paleozoic era and is named after the province of Perm, Russia, where rocks of this age were first studied.

The global geography of the Permian included massive areas of land and water. Models indicate that the interior regions of this vast continent were probably dry, with great seasonal fluctuations, because of the lack of the moderating effect of nearby bodies of water, and that only some parts of the supercontinent received rainfall throughout the year. The ocean itself still has little known about it. There was extensive glaciation in southern parts of the landmass, shown by glacial striations on Permian rocks from what are now Africa, South America, and Antarctica, and extensive deposits of windblown soil indicate a very dry climate. However, there are indications that the climate of the Earth shifted at this time, and that glaciation decreased, as the interiors of continents became drier.

One of the most striking transitions in the evolution of life occurred when mammals evolved from one lineage of reptiles. This transition began during the Permian…

Permian rocks are widely distributed in New Zealand’s South Island and also occur in the Northland region of the North Island, where they are the oldest known rocks. In some places the deep sedimentary marine series that was laid down is up to 20 kilometres thick and one of the most complete Permian sequences preserved anywhere in the world. The biggest build up of volcanic rocks made the Takitimu Mountains near Redcliff, Waiau Valley, where the pile of tuff layers is 14 kilometres thick. Unfortunately Permian fossil outcrops are hard to find, but at Arthurton, near Gore, complete shells of Atomodesma, a bivalve, can be found. And of course a whole leaf of Glossopteris plant has been found at Productus Creek

There is no mention of the Permian trace fossils of Southland but the rocks in which they occurred, which would likely have bordered on the Waiau Valley, including the Eglinton Valley, are identified in general terms.

As Te Ara The Encyclopedia of New Zealand notes, the end of the Permian period marks earth’s largest ever extinction – two-thirds of plant and animal life died out, probably as a result of a sudden climate change.

**************

The next Post in this Series looks at another, maybe related, explanation for the “fossilised worm cast stones” found on Gemstone Beach and the beaches of Riverton in Southland.

The Fossilised Worm Cast Stones of Gemstone Beach and Riverton – Part Three: What Kinds of “Traces” are on These Stones?

“Fossilised worm casts” are trace fossils, and I have found them in stones deposited on the beaches between Orepuki and Riverton at the bottom of the South Island of New Zealand. In the first Post in this series, I noted how these stones are especially associated with Gemstone Beach, near Orepuki. In the second Post, I introduced the idea of “trace” fossils. This Post looks at the shapes of the traces of the “worm casts” in more detail.

The traces on these fossil worm cast stones exhibit different shapes. A handful of the stones are crowded with different shaped traces:

Other stones have only one trace, or a partial trace, or a very faint trace:

It appears that a micro-faultline that has split this trace:

On the occasional stone, the trace is noticeably raised in relation to the rest of the stone:

However, on the vast majority of the stones, the trace has worn away at the same rate as the rest of the stone.

Let’s look more closely at the shape of the traces. One of the stones I collected has these shapes on it: 

traces 1

Are “A” and “B” essentially the same shape, “B” being a bit more stretched out somehow? There are also a number of much smaller and less complex shapes “C” – are these made by a different animal altogether? Or are they parts of shapes similar to “A” and “B”?

In the next stone (below), “D” seems similar to “B” in the previous stone, but “E” and “F” appear to be different from these. “E” is not segmented, and “F” is not lineal. Unless “E” is in effect a side view of “D”, and “F” is a view of “D” from the top or from below. It is important to be aware that a trace will look different depending on whether it is lying along the surface of a stone or “emerging” from it. 

traces 2bb

The next trace shape seems to change along its length, being clearly segmented at the bottom but much less so at the top. Is the very top end part of the same trace? Or is it a different one altogether?

traces 3

On this stone (below), is “G” the same kind of trace as “H”, with “H” being a bit more worn away? Or are they different traces altogether?

traces 4bb

And is this next shape different from all the others?

traces 5

Some of the stones have blank featureless stripes on them, such as “I” on the stone below:

stripe1cc

Is such a stripe a worn, or less-worn, version of the segmented trace to the left of it? Or was a different kind of animal or activity involved?

What are we to make of the trace shapes on this stone (below)? Are the traces all different or are they variations of the same shape? Or are they parts of one shape that has been partly worn away? If they are different shapes, might they have still been made by the same animal?

traces 6

Finally, an example of complexity. The stone below contains a number of trace shapes, many of which we have already seen in the stones above. However, the lineal feature marked “J” is a long complex shape not previously encountered. How would we make sense of it? What kind of animal would have made such marks, and how?   

traces 7bb

The next Post will present the most common shape of the traces on the fossilised worm cast stones I have collected. The Post after that will try to identify this trace based on the literature that examines in detail the kinds of traces left behind by animals on the floor of the sea.

The Fossilised Worm Cast Stones of Gemstone Beach and Riverton – Part Two: What is a Trace Fossil? From Dinosaur Traces to Sea-Pen Traces

“Fossils are the preserved evidence of past life. They may include organic remains such as wood, shells, bones and teeth that have been buried, mineralised, and turned to stone” (Te Ara Encyclopedia of New Zealand). Fossils are very important to geology because they are used to date sedimentary rock strata, just like pottery and other artifacts are used to date archaeological layers. Fossils don’t survive the forces that produce metamorphic rocks nor the extreme heat associated with volcanic rocks, so they are found only in sedimentary rocks.

Fossil worm cast stones, like those above, introduced in the first Post in this series, are examples of trace fossils (also known as “ichno-fossils“), which are different from most other types of fossils. In the book, “A Photographic Guide to Fossils of New Zealand“, written by Hamish Campbell, Allan Beu, James Crampton, Liz Kennedy and Marianna Terezow (2013), it is pointed out that trace fossils are not the organic remains of dead organisms. “They include marks, traces, tracks, burrows and deposits that relate to animal and plant behaviour, dead or alive” (page 9). The authors go on to state that trace fossils “record an animal’s moving, exploring, escaping, hiding, breathing, hunting feeding, excreting, reproducing, growing, playing fighting, dying, or resting” (page 10).

Take as an example of a trace fossil, the footprints which record the movement of a dinosaur. In Bolivia is a limestone cliff on the face of which can be seen the footprints of at least eight different dinosaur species, left as trace impressions over 68 million years ago. A news article in “The Guardian” in 2011 explains how the footprints were made: “The creatures’ feet sank into the soft shoreline in warm damp weather, leaving marks that were solidified by later periods of drought. Wet weather then returned, sealing the prints below mud and sediment. The wet-dry pattern was repeated seven times, preserving multiple layers of prints. The cherry on the cake was added when tectonic activity pushed the flat ground up to a brilliant viewing angle.” See the photos below.

Dinosaur trace fossil footprints have also been found in New Zealand, in northwest Nelson. In 2009, GNS Geologist Greg Browne came across 70-million year old dinosaur footprints in sandstone around the shores of Westhaven (Whanganui) Inlet. They were the very first dinosaur footprints to be recognised in New Zealand as well as providing the first evidence of dinosaurs in the South Island. 

There is an excellent YouTube clip in which Greg Browne shows the dinosaur trace fossil footprints he discovered, discusses how they were made, and points out the information provided by such fossils. According to a 2016 news report, it is thought that the footprints were most likely made by the colossal sauropod dinosaurs, the largest animals to have walked on Earth, growing to about 40 metres in length and weighing more than 100 tonnes (there is a depiction of a sauropod below the next video clip, the photo on the left). But there can often some doubt over exactly what dinosaur makes trace fossil footprints. We don’t have live dinosaurs whose contemporary footprints we can study!   

In May this year, a significant trace fossil find in Otago, New Zealand, happened when Michael Johnson found some moa footprints that had been exposed in a streambed. Floods had scoured away the bed to expose the footprints, which had been made in clay.   

Those who have studied dinosaur trace fossil footprints have pointed out that different substrates (sand, mud, silt etc.) and environments (land, stream, coast etc.) offer different chances of preserving them. An excellent diagram is in the photo below right.

Similar issues arise with the trace fossils of small marine animals like those whose markings have been left on the stones of the south coast. In “A Photographic Guide to Fossils of New Zealand” are only two trace fossil entries, on page 64, the first of which looks similar to the fossil worm casts found at Gemstone Beach and Riverton (see below). In the second entry, it is noted that the animal responsible for the traces is unknown despite the distinctiveness of the trace.

Another New Zealand example of a trace fossil can be found in Jocelyn Thornton’s (2013) “The Field Guide to New Zealand Geology”. On page 64 she refers to “the feeding traces of a wormlike creature, possibly something like a sea-pen”, these traces being “rows of grey arrowheads” and “swirling patterns” (see photo of text extract below). A sea-pen actually doesn’t look like a worm (see photos below) but it has a “peduncle” to anchor itself in sand or mud. A “peduncle” is a stalk-like part by which the sea-pen is attached to its substrate, by burrowing into it. As a New Zealand guide to sea-pens puts it: “Virtually all sea pens attach to the soft substrata of benthic sediments by an unbranched rootlike and sausage-shaped muscular peduncle enabling them to stand erect” (page 3 of “Pennatulacea (Sea Pens) Descriptions for the New Zealand Region“, 2014, by Gary Williams, Di Tracey and Erika Mackay). I guess it is the peduncle that will leave burrow-like traces behind, but it’s difficult to see them as having much length or going in a curving direction.  

Nevertheless, this example from Thornton’s book raises again that important point about the kind of trace fossils I am interested in (the kind of traces left by marine worm-like animals). The point is that there is a distinction between the trace itself and the animal that makes the trace. What we have available to us are the traces – we then have to work out what animals made the traces (just as the dinosaur researchers have to do). And it may be that more than one kind of marine animal can make the same kind of trace. And can different traces be made by the same animal?

Furthermore, other things than animals can make “traces” on the sea floor or on rocks. Three different kinds of “pseudofossils”, commonly mistaken for trace fossils, are referred to in “A Photographic Guide to Fossils of New Zealand”. These are: sedimentary features such as ripples, caused by sea currents acting on sand, silt and mud (see photo below left); mineral growths, such as iron and manganese hydroxide minerals growing on the surface of a crack in a rock (see photo below middle); and structural features, such as clay minerals having a preferred orientation leading to regular patterns in a rock (see photo below right).

For more on pseudofossils, see Western Australia Dept of Mines, Industry Regulation and Safety and Wikipedia

In the next Post in this series, I will examine the shapes of the traces found in the fossilised worm cast stones of Gemstone Beach and Riverton. Later Posts will then try to make sense of these shapes.

The Fossilised Worm Cast Stones of Gemstone Beach and Riverton – Part One: Initial Identification

The tourist information on Gemstone Beach near Orepuki, 29 kilometres west of Riverton, sometimes mentions that fossil worm cast stones can be found there. For example: “A few hours beachcombing could easily yield gems such as hydrogrossular, jasper, fossil worm casts and the elusive sapphire” (Heritage Trail website). The Heritage Trail sign that used to stand at Gemstone Beach also mentions fossil worm casts.

Gemstone Beach Heritage Trail
Source: https://talltales.me/2013/02/24/the-south-of-the-south/photo-2-01-13-10-30-21-am

Over the past couple of years, I have believed that the sort of stones being referred to here would have within them, or on them, the fossilised remains left by worms at the bottom of the sea, these remains being the castings excreted by them as they fed. This series of Posts reports on the research I have done to check out this belief.

The photos below show what I have come to think of as fossil worm cast stones. They have all been collected by myself mostly from Gemstone Beach but some also from Riverton beaches:

In a small entry on types of fossils written by Hamish Campbell in 2006 in Te Ara The Encyclopedia of New Zealand, the example of a fossilised worm burrow is very similar to the stone in the photo centre right above. Campbell writes: “The worm-like impression is called a trace fossil, as it shows traces left by a worm burrowing through mud.” 

Te Ara fossil types
Top left is a rock with a fossilised worm burrow. Source: https://teara.govt.nz/en/photograph/9020/three-types-of-fossil

Note that Campbell mentions “burrows”, not “casts”. Maybe the distinction is important – we will return to this in a later Post.

Furthermore, the Riverton Museum Te Hikoi includes two “worm trace fossil” stones in one of it rock drawers (see photo below). They look similar to some of the ones I have collected on Gemstone Beach and Riverton.

Te Hikoi wc
Riverton Museum Te Hikoi display. Photo taken with permission.

Jocelyn Thornton’s (1985) book, “Gemstones“, has a page on “Orepuki Beach Pebbles” (page 36). She refers to a group of stones (number “5” in her diagram) as follows: “Those at the top of this group clearly show layers of mud, worm trails and wave ripples…” (see photos below). She uses the term “trail” and not “cast”. None of these stones really look like the fossil worm cast stones I have found.

The next Post in this series will look more closely at what a “trace” fossil is.