The grandfather of the shells symbol of the Camino

[JustOneGuy]

As I keep dreaming about the time when I will be able to start a real Camino , I was thinking about the origin of the shell represented in the Compostela. I mean the so called concha (the shell), not the symbol.

As everyone knows, I guess, it is a shell of the Pectinidae family, which features between 250 and 900 species (the subject is controversial, though.) If, however, one also includes fossil species, then one reaches about 7000 different species. The Pectinidae have had a rather troubled history: very common in the Mesozoic (the age of reptiles), they became much rarer at the end of that period, in the Cretaceous, before spreading again in the Tertiary (66-2.6 million years ago).

These shells can be found in all the world's oceans... and in many dishes served at the table. Fortunately for us and unfortunately for them.

Pectinidae features several quite unique properties. By studying the subject a bit, I ‘discovered’ for example that scallops have dozens, sometimes hundreds (depending on the species) iridescent eyes. Also, that they can move in both directions, but while forwards they zig-zag, backwards they simply go straight.

But... no, they don't have legs. Or at least, we should not discuss the topic in public:

My interest in the subject arose when I found several Pectinidae embedded in some strata of a asturian beach. In fact, my avatar is from a photo taken there.

It looks very much like some of the beaches in the South West of the UK. It is interesting to note that Pectinae originated in the Triassic (about 200 million years ago), whereas some of the north coast of Spain is much older: some rocks date back as far as the Precambrian (4.6 billion years ago).

I added a few photos of those Pectinidae's fossils I hope someone enjoys:



The photos were taken at the right end of Playa de Vega, near Ribadesella (many Trilobite fossils were found during the excavation of a nearby highway tunnel):


NOTES:

I hope I got everything right, but I will be grateful to anyone more knowlegeable who will correct me or will add more interesting information on the topic.

Last but not least, I encourage people to look for them if interested, but please, take a photo and leave the specimen there for others to enjoy. Thanks!

 

[LeslieC]

Thanks, @JustOneGuy. I hadn't realised there were fossils around there.

In your first photo, the two longer shells above the scallop look like belemnites, a type of extinct squid. I've seen rocks containing hundreds of them near Oaro, on the east coast of New Zealand's South Island.

If that's what the Asturian ones are, I think that would date the rocks to the Jurassic period - around 140-200 million years old.

 

[William Garza]

As I keep dreaming about the time when I will be able to start a real Camino , I was thinking about the origin of the Compostela. I mean the shell, not the symbol.

As everyone knows, I guess, it is a shell of the Pectinidae family, which features between 250 and 900 species (the subject is controversial, though.) If, however, one also includes fossil species, then one reaches about 7000 different species. The Pectinidae have had a rather troubled history: very common in the Mesozoic (the age of reptiles), they became much rarer at the end of that period, in the Cretaceous, before spreading again in the Tertiary (66-2.6 million years ago).

These shells can be found in all the world's oceans... and in many dishes served at the table. Fortunately for us and unfortunately for them.

Pectinidae features several quite unique properties. By studying the subject a bit, I ‘discovered’ for example that scallops have dozens, sometimes hundreds (depending on the species) iridescent eyes. Also, that they can move in both directions, but while forwards they zig-zag, backwards they simply go straight.

But... no, they don't have legs. Or at least, we should not discuss the topic in public:View attachment 178713

My interest in the subject arose when I found several Pectinae embedded in some strata of a beach in Galicia where I went in the hope of finding some exposed fossils.

In fact, my avatar is from a photo I took in Asturia, at a beautiful and secluded beach where I went to look for fossils (see below).

It looks very much like some of the beaches in the South West of the UK. It is interesting to note that Pectinae originated in the Triassic (about 200 million years ago), whereas some of the north coast of Spain is much older: some rocks date back as far as the Precambrian (4.6 billion years ago).

I added a few photos of those Pectinidae's fossils I hope someone enjoys:

View attachment 178714 View attachment 178715

The photo were taken at the right end of Playa de Vega, near Ribadesella (close by where many Trilobite fossils were also found during the excavation of a highway tunnel):

View attachment 178756
NOTES:

I hope I got everything right, but I will be grateful to anyone more knowlegeable who will correct me or will add more interesting information on the topic.

Last but not least, I encourage people to look for them if interested, but please, take a photo and leave the specimen there for others to enjoy. Thanks!

A few hours from here, i found a few while on a jobsite..the limestone of the hill country seems infested with smaller versions.

 

[JustOneGuy]

Thanks, @JustOneGuy. I hadn't realised there were fossils around there.

In your first photo, the two longer shells above the scallop look like belemnites, a type of extinct squid. I've seen rocks containing hundreds of them near Oaro, on the east coast of New Zealand's South Island.

If that's what the Asturian ones are, I think that would date the rocks to the Jurassic period - around 140-200 million years old.

Thanks so much, @LeslieC.

Actually I was just wondering what those are. Now I know they are belemnites . Thanks also for the period identification.

 

[Tincatinker]

As I keep dreaming about the time when I will be able to start a real Camino , I was thinking about the origin of the Compostela. I mean the shell, not the symbol.

As everyone knows, I guess, it is a shell of the Pectinidae family, which features between 250 and 900 species (the subject is controversial, though.) If, however, one also includes fossil species, then one reaches about 7000 different species. The Pectinidae have had a rather troubled history: very common in the Mesozoic (the age of reptiles), they became much rarer at the end of that period, in the Cretaceous, before spreading again in the Tertiary (66-2.6 million years ago).

These shells can be found in all the world's oceans... and in many dishes served at the table. Fortunately for us and unfortunately for them.

Pectinidae features several quite unique properties. By studying the subject a bit, I ‘discovered’ for example that scallops have dozens, sometimes hundreds (depending on the species) iridescent eyes. Also, that they can move in both directions, but while forwards they zig-zag, backwards they simply go straight.

But... no, they don't have legs. Or at least, we should not discuss the topic in public:View attachment 178713

My interest in the subject arose when I found several Pectinae embedded in some strata of a beach in Galicia where I went in the hope of finding some exposed fossils.

In fact, my avatar is from a photo I took in Asturia, at a beautiful and secluded beach where I went to look for fossils (see below).

It looks very much like some of the beaches in the South West of the UK. It is interesting to note that Pectinae originated in the Triassic (about 200 million years ago), whereas some of the north coast of Spain is much older: some rocks date back as far as the Precambrian (4.6 billion years ago).

I added a few photos of those Pectinidae's fossils I hope someone enjoys:

View attachment 178714 View attachment 178715

The photo were taken at the right end of Playa de Vega, near Ribadesella (close by where many Trilobite fossils were also found during the excavation of a highway tunnel):

View attachment 178756
NOTES:

I hope I got everything right, but I will be grateful to anyone more knowlegeable who will correct me or will add more interesting information on the topic.

Last but not least, I encourage people to look for them if interested, but please, take a photo and leave the specimen there for others to enjoy. Thanks!

Nice exposition but confusions there are also. The Compostela is a nice piece of paper with some writing on it and a picture of some random Pectinidae.

The shell, the concha, that few grams of additional weight most pilgrims seem happy to carry is not a Compostela. The association is attributed to the scallops that clung to St Jame’s funerary boat (an unusual bit of behaviour for a scallop) and for all we know propelled all the available bits of him from Jerusalem to Galicia. A scallop in panic mode has a fair turn of speed so I guess all things are possible.

That said a confabulation of seashell and Pilgrim Proficiency Certificate is probably best avoided.

I used to find Pectinidae fossils in the Triassic shales of Lyme Bay in Dorset though our quarry was always Ammonites and Plesiosaur

 

[JustOneGuy]

Nice exposition but confusions there are also. The Compostela is a nice piece of paper with some writing on it and a picture of some random Pectinidae.

The shell, the concha, that few grams of additional weight most pilgrims seem happy to carry is not a Compostela. The association is attributed to the scallops that clung to St Jame’s funerary boat (an unusual bit of behaviour for a scallop) and for all we know propelled all the available bits of him from Jerusalem to Galicia. A scallop in panic mode has a fair turn of speed so I guess all things are possible.

That said a confabulation of seashell and Pilgrim Proficiency Certificate is probably best avoided.

I used to find Pectinidae fossils in the Triassic shales of Lyme Bay in Dorset though our quarry was always Ammonites and Plesiosaur

Thanks for the clarification, @Tincatinker. I added a few words at the beginning to correct myself.

I also kind asked @ivar to edit the title of this thread accordingly.

Lucky you that found a Plesiosaurus. I found some trilobites and ammonities in Wales when living there, nothing more than that.

 

[Tincatinker]

Honesty prevails. We found one metatarsal. Spent a week looking for the source in the shales. Never found it. Did find a few ammonite that had aggregated with iron pyrites in the sludge below Black Ven. The local jewellery makers we’re chuffed

 

[Peregrinopaul]

As I keep dreaming about the time when I will be able to start a real Camino , I was thinking about the origin of the shell represented in the Compostela. I mean the so called concha (the shell), not the symbol.

Your interesting post certainly got my attention @JustOneGuy. On all my caminos I don’t remember finding a single fossil, not for the want of looking. I’ve seen lots of specimens in museums, of course - this one in Southern France.

The colloquial name for the fossil is Coquille St. Jacques!
And here are some displayed on my bookshelf. All picked up on my local beach, and they have all accompanied me on Camino at one time or another.


The strata at Playa de Vega are definitely Jurassic, as @LeslieC suggested. They are the same rocks as at Lyme Bay, @Tincatinker, which are the same age.

And just being picky here, but the pre-Cambrian rocks exposed on the coast will be much (much) younger than you suggest. Perhaps approaching 1billion years (not to be sniffed at, mind you). Just for the record, the oldest fragment of the earth’s crust ever found is a zircon crystal dated at 4.4 billion years, found in the Jack Hils, in the outback a couple of hundred kilometres away from where I live.

 

[Peregrinopaul]

Those are modern shells on my bookshelf, not fossils,of course.

 

[VNwalking]

I added a few photos of those Pectinidae's fossils I hope someone enjoys:

I used to find Pectinidae fossils in the Triassic shales of Lyme Bay in Dorset though our quarry was always Ammonites and Plesiosaur

A what!?? Sheesh.
I envy you both. I grew up with basalt and graduated to living where there's andesite.
Fun in their own ways, but not half so cool as that.
And I haven't ever seen anything so gorgeous on a camino, either (like Paul, not for want of looking...).

Last but not least, I encourage people to look for them if interested, but please, take a photo and leave the specimen there for others to enjoy. Thanks!

Yes. Thanks for leaving them be. Everyone should get to see things like this.

 

[JustOneGuy]

The strata at Playa de Vega are definitely Jurassic, as @LeslieC suggested. They are the same rocks as at Lyme Bay, @Tincatinker, which are the same age.

And just being picky here, but the pre-Cambrian rocks exposed on the coast will be much (much) younger than you suggest. Perhaps approaching 1billion years (not to be sniffed at, mind you). Just for the record, the oldest fragment of the earth’s crust ever found is a zircon crystal dated at 4.4 billion years, found in the Jack Hils, in the outback a couple of hundred kilometres away from where I live.

Thanks for the information, @Peregrinopaul !

I am reading a few articles on the geology of the area but it is not easy to understand exactly where and when for individual locations, partly because I am not a geologist by training (I am an astronomer) although over the years I am becoming more and more passionate about the subject.

However, I did not mean to say that those rocks are Precambrian, or that they are 4.6 billion years old, but that Precambrian rocks have been found in that area (I cannot find the reference unfortunately).

And in fact the origin of that section of the astrurian coast is referred to as “Jurasian model of fluvial sedimentation” (see e.g. this old paper. Also more recent studies confirm what you and others wrote).

 

[JustOneGuy]

And the title of this thread has been updated: thanks @ivar !

 

[VNwalking]

For those who enjoy getting into the weeds with this kind of thing, here's the geological map of the Playa de Vega.

https://info.igme.es/cartografiadigital/datos/magna50/jpgs/d0_G50/Editado_MAGNA50_31.jpg

 

[JustOneGuy]

Thank you! That's what I was looking for.

The area where I saw those fossils (and were I took the photos) should be more or less near the red arrow:

It is definitively marked as 14 and 15 (Jurassic) in the legenda. Unfortunately, I am not completely able to understand the stratygraphic column, but I got the general idea...