Zandmotor hunt: a bountiful of bivalves

[Max-fossils]

Hi all,

 

This weekend, after the long, boring and annoying winter months (it's always mildly cold, but very windy and rainy in the Netherlands in winter... horrible fossil hunting conditions) spring finally let out the tip of its nose, with a nice sun, blue sky and decent temperature. About time! We all know what this means... time to do some fossil-hunting! 

 

So on Sunday morning I woke up, prepared my fossil hunting equipment (mainly bags and boxes; no tools needed for this beach), made myself a lunch, and set out at 13:00 to the bus. The bus ride to Kijkduin takes me about an hour, so I arrived at the beach at 14:06. But, as usual, because it's by bus I'm not dropped off at the ideal spot, so I have to walk about an hour on the beach, due south-west, to actually get to the Zandmotor. But that wasn't much of a problem... this part of the beach already has a few fossils to yield, although not as many, so you can start the fossil hunting right away. 

Didn't find anything significant though in that first stretch. You're literally walking on lots of Eemian fossil shells, but these species are all very common. Spisula solida, Cerastoderma edule, C. glaucum, and Macoma balthica are just not worth picking up, unless it's a specimen that stands out to me (unusual size, pathologies, weird colors, etc). 

 

Here's a map to better illustrate the places I will mention. Note that it's approximate. Also, the sand cliffs and the shell banks often move around, we are after all on a beach with lots of wind and water movement, so these positions aren't defined. But this is what was the case this weekend. And the pink Zandmotor "limit" isn't accurate either, it's more my view as in "this is good fossil-hunting territory". By the way, that red S is where the bus drops me off. Oh, and that big puddle in the middle of the beach is actually a very popular kite-surf spot, especially for amateurs because there are no waves. 

 

This time I started off the hunt at the "sand cliffs" as I like to call them, (2m tall at the highest point, so not real cliffs), then went on to an area more to the south of the Zandmotor (at the bottom of the dark blue line on the map). It was my first time properly hunting that little area, and it turns out it's actually a good spot, I found lots of good bivalve fossils there! After an hour or two I sat down to eat my lunch (yes, a very late lunch, but time flies by when you're fossil hunting! I'm actually still surprised I remembered to eat my lunch at all, I usually get so caught up in the hunt that I often just completely forget to eat my lunch at all ), then went onto the richest part of the Zandmotor when it comes to shells, the..... (drumroll please)............. shell banks! I know, very unexpected! The real Eemian shell banks are usually lying on the north-center of the Zandmotor, between the cliffs and the shoreline. That is when I made my two favorite finds of the day: a gorgeous Propebela turricula, and a bit later, Gari fervensis! 

 

After a total of about 5 hours hunting, I decided it was time to get back home, so I called it a day. But man was it a good day! I found an incredible diversity of fossil shells, especially bivalves. 

 

Onto some pictures, starting with some location pics. 

[Max-fossils]

Rotterdam in the distance here. There were more people on the beach than usual, but then again, it was the first 'warm' Sunday in a good while. 

The white tower you can kind of discern in this picture approximately marks the center of the Zandmotor. 

[Max-fossils]

I may like fossil shells better, but do also have a weakness for modern ones too. And seeing this huge Mya arenaria shell just laying there (it was dead unfortunately) with the whole body still there is pretty cool. This specimen was surprisingly big. 

[Max-fossils]

And some sunset pics of the last bit of the hunt, because why not  

[Gizmo]

Great pics and info, thanks for posting! 

[Max-fossils]

Onto the actual finds I made!

Just to illustrate the incredible diversity of shells we have here, I will show at least one couple of pictures of each species found today! So also the common and fragmentary ones will be shown, just for the fun of it  

All these shells are from the Eem Formation; Eemian interglacial, Pleistocene (unless stated otherwise). 

 

1) A perfect Mimachlamys varia scallop

[Max-fossils]

2) A fantastic egg cockle, Laevicardium oblongum crassum

[Max-fossils]

3) My favorite find of the day: a small and kinda worn Gari fervensis. But this species is rare, and I love it very much, so I was super happy to find this one  

I have a much better example that I found on the Maasvlakte 2 a long time ago, you can find it in the TFF Collections. My new one is nowhere as nice as my older one, but it's my first one of the Zandmotor and that's good enough to make me very happy  

[Max-fossils]

4) A cool Donax vittatus

[Max-fossils]

5) I often talk about this weird dude, the Corbicula cf fluminalis! We still don't exactly know how old this freshwater critter is, but it's not Eemian (maybe 400'000 years old?)...

[Max-fossils]

6) Gotta love the artemis shells!!! Here we have a gorgeous Dosinia exoleta 

[Max-fossils]

7) And its equally gorgeous little brother, Dosinia lupinus  

[Max-fossils]

8) A surprisingly well-preserved incomplete shell from something in the Pharidae family (I still need to figure out which one, they're a pain to identify). You don't often see them with the hinge in such a good condition!

[Max-fossils]

9) And another Pharidae family shell piece. This one is clearly a different species, but I also don;t know which one. Got some IDing to do, but luckily I have all the documents necessary. 

[Max-fossils]

10) A quite small and beautiful Acanthocardia tuberculata specimen. I found a bunch of them, but most of them are massive complete ones that are nowhere as cute as this one  

 

[Max-fossils]

11) And this one is very cool... might be just a fragment, but its sculpture is just good enough to see that this is part of the much rarer Acanthocardia echinata! A first for me, good to have this species be confirmed on the list  

[Max-fossils]

12) A very big specimen Cerastoderma glaucum, a common species, but rarely in this size (and with such a nice blue hue). 

[Max-fossils]

13) The boreal astarte shell, Tridonta borealis. Also a weird one, because it's a coldwater species (still alive around namely Iceland) yet found in warm Eemian localities... Scientists are thinking it might be a bit younger, from the Weichselian, some 80'000 years old. 

[Max-fossils]

14) A perfect Gastrana fragilis!

[Max-fossils]

15) Followed by another one of the same species, but this one is very ugly! Still perfect though. Pathological specimen? I think I like it even more than the normal perfect one  

[Max-fossils]

16) A very nice Anomia ephippium, easily mistakeable with the common oyster Ostrea edulis if you don't look well enough. 

[Max-fossils]

17) Speak of the devil... here we have a common oyster! Ostrea edulis. Although to be honest, this species isn't exactly the devil... that title is better suited to the Japanese oyster Crassostrea gigas, an invasive species that is driving our common oyster to extinction   Or are humans the evil ones for having brought that species here? 

[Max-fossils]

18) Gotta love these Venerupis decussata. Here a nice big specimen. 

[Max-fossils]

18) And another smaller one of the same species, with slightly better conservation. 

[Max-fossils]

20) Followed by their much more common brother the Venerupis senescens, a species sometimes used as guide fossil for the Eemian.