Two days in the famed Holzmaden quarry, Germany

[Italo40]

Germany is one of the top fossil-hunting destinations in Europe, having plenty of easy-to-access, highly productive localities that are visited every day by experienced collectors and families alike.

The Swabian Jura (or Swabian Alb) region (southwestern Germany, near Stuttgart) has a highly significant geological heritage, which is part of the network of the UNESCO Global Geoparks since 2015.

 

The most popular destination within the park is the area around the village of Holzmaden. In the early 20th century, several quarries dotted the area. Nowadays, the mining operations have almost completely ceased, but one or two of them can still be accessed, for instance the ‘Schieferbruch Ralf Kromer’ quarry, located in the neighboring village of Ohmden. By paying a 4 euros daily ticket, you can access the place (in our case even with the car) and collect fossils. You may keep everything you find, except for the highly unlikely case when you find something that is of scientific interest.

 

The rock which is exploited is a finely laminated limestone, called Posidonia Shale. It has a dark colour, due to the high amount of organic matter and mineral oil. These rocks are Toarcian (Lower Jurassic, around 180 million years ago) in age. At the time a sea extended over the area, which was affected by a monsoon climate. During summer months, water stratification led to the bottom waters and sea floor being oxygen-free. As a result, bacteria and scavengers were absent: organic matter was very slowly decomposed and, if it was quickly covered by sediment washed in, it had a high chance of being preserved, turning with time into fossils.

 

The taphonomic conditions explained above account for the often exceptional preservation of Holzmaden fossils. Several complete specimens of ichthyosaurs, plesiosaurs, thalattosuchians (so-called sea crocodiles) and fish are known. Flying reptiles and dinosaurs are extremely rare. Molluscs (bivalves, ammonites) and crinoids are very abundant, whereas arthropods and echinoderms are rare.

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I visited the Swabian Alb Geopark in August 2022 with a friend (@Marcosaur) , stopping at the Kromer quarry for two days. Here follows a brief account of my experience:

 

The Kromer quarry yields a very high number of ammonites, ranging in size from a few millimeters to 40 cm or even more. Brachiopods and bivalves are less common. Crinoids and fish are not preserved in the layers exposed in this quarry; disarticulated reptile bones (chiefly vertebrae) and teeth can be occasionally found and if you are extremely lucky, you may even find articulated specimens.

 

First, here is a panoramic view of the quarry from near the entrance. The fossil-rich layers are best exposed at the opposite end, but, not knowing this, my friend and I began excavating in a different location.

 

Soon, however, we realized that and we moved to a better site.  At this point, things improved quickly. We could work on larger limestone surfaces, which split more easily, so that we could prevent the fossils from breaking. Here you can see a panoramic of the quarry from above:

 

View of our definitive excavation site; most of the large slabs lying on the ground were packed with fossils:

 

Ammonites were extremely abundant and they made up more than 90% of the fossils that we found. They are always flattened and pyritized, thus being golden yellow in colour. When you split a rock, you get part and counterpart. Three genera are predominant in the Kromer quarry: Dactylioceras, Lytoceras and Harpoceras. The former attains small to medium size, whereas the other two are represented by large specimens.  A slab could preserve countless Dactylioceras shells on its surface, making the slab itself almost completely yellow and shining, a delight to behold! We recovered two or three Harpoceras specimens, 20 to 25 cm in size. We didn’t find any Lytoceras, only fragments; however, other people working next to us did find some and they were massive, more than 30 cm in size!

 

Here you can see several Dactylioceras specimens:

 

And here a massive slab, fully covered by countless Dactylioceras!

 

Bivalves and brachiopods are usually not pyritized and dark in colour, thus being less easy to spot on the slab surface. We recovered only a handful of them, but they were quite well preserved.

Unfortunately, we didn’t find any vertebrate fossil and, as far as we know, neither did any other people working during the two days that we were there. If they had, the news would have spread pretty quickly!

 

The limestone is quite hard and it often doesn’t break along a line. The thicker the rock, the easier it can be split in flat surfaces, revealing part and counterpart of the fossil specimens. When working with large slabs, a crowbar is essential. It was by lifting such a heavy slab that we saw before our eyes a complete Harpoceras: it was our best find and we committed not to break it, by carving out a slab that we could then lift and put aside. Soon we exposed another specimen right next to it. Here you can see how that looked: 

 

Two other Harpoceras ammonites:

 

Another Harpoceras, this time a counterpart:

 

To sum up, this two-days trip in the Kromer quarry was highly succesfull and rewarding, despite a slow start in the first day and the hot temperatures. The trunk of the car was fully loaded by the end of the second day!

I highly suggest to anyone visiting southern Germany to stop at this place, you won't be disappointed. Besides, you can then visit the impressive UrweltMuseum Hauff in Holzmaden, where many wonderful fossils are on display. I will upload a post about my visit to the museum soon.

 

Last thing, my friend and I recorded a short video (in two parts) at the quarry, where we kept track of our progress and finds. The dialogues are in Italian only, but I guess that you could let the fossils speak for themselves!

Here it is

 

- Part 1: 

 

- Part 2: 

 

If you want further information, here are two useful links:

- Website of the quarry: http://www.schieferbruch-kromer.de/

- Overview of the Posidonia shale: http://www.holzmaden.com/Holzmaden_fossils_informations.html

 

Thank you for the attention, 

Italo40

 

 

 

Edited December 22, 2022 by Italo40

[Tidgy's Dad]

Marvelous report, what a great couple of days! 

Any chance of a brachiopod photo or two, please? 

[historianmichael]

Very cool! Thank you for the report. The Harpoceras is impressive 

[ClearLake]

Very nice, looks like a fun place to visit. 

[Italo40]

1 hour ago, Tidgy's Dad said:

Marvelous report, what a great couple of days! 

Any chance of a brachiopod photo or two, please? 

Thank you! Unfortunately I don't have any pic at hand and all the fossils are stored away until I can find some room to exhibit there in my little collection. I'll make sure to take some pics of the finds when I'll unpack them.

 

54 minutes ago, historianmichael said:

Very cool! Thank you for the report. The Harpoceras is impressive 

 

Indeed! We had a short stay and lacked heavy equipment, otherwise we could have found many more for sure. A team next to us found a slab with Harpoceras and Lytoceras specimens on it, it was huge (and you can see it in the 2nd part of the video linked above)! 

Edited December 22, 2022 by Italo40

[rocket]

Holzmaden is a great place to dig. Good Ammonites are really not easy to find, yes Ammonites are common, but a good one can take some days...

@Tidgy's Dad: Brachiopods are really rare..., Discinisca could be found sometimes, others... I can look in our collection, we have a slab with several on it

Edited December 22, 2022 by rocket

[Tidgy's Dad]

2 hours ago, rocket said:

Holzmaden is a great place to dig. Good Ammonites are really not easy to find, yes Ammonites are common, but a good one can take some days...

@Tidgy's Dad: Brachiopods are really rare..., Discinisca could be found sometimes, others... I can look in our collection, we have a slab with several on it

Yup, I know they're pretty uncommon there, but I'd really love to see your slab of Discinisca, please. 

Or post the slab to me, and I'll take some nice photos.

[rocket]

16 minutes ago, Tidgy's Dad said:

Or post the slab to me, and I'll take some nice photos.

, thats a cool idea. It is cold here, I will pack me in the parcel, too. Morocco seems to be better climate for the moment 

I go to take pics of the Slab next days, it´s nice and really unusual

[Ludwigia]

You should check out belemniten's Holzmaden album. He's a local that has lots of experience collecting in this quarry and has made some very nice vertebrate finds.

[Neanderthal Shaman]

Nice, I have a D. athleticum from Germany and it's one of my favorites. The orange coloration on them is very appealing 

[Jeffrey P]

Excellent report. Great photos! Wonderful videos! Thanks for sharing your adventures. You've given me another reason to return to Germany. 

[rocket]

Here is a pic of your brachiopode-slab, showing some of the rare Discinisca papyracea (MÜNSTER)

 

 

[rocket]

On 12/22/2022 at 10:54 PM, Ludwigia said:

You should check out belemniten's Holzmaden album. He's a local that has lots of experience collecting in this quarry and has made some very nice vertebrate finds.

 

nice material, this is what you can find when you often, Belemnites, Ammonites, Ichthyosaur-Remains, Teeth and some more. I love the Holzmaden-Posidoniaslate, fantastic Material and a great preservation. Some of the Ichthyosaurs are fossilized with soft-tissue, incredible!

[rocket]

just for showing, one of the fossils you will only find one time in your life..., large and nearly perfect Pachycormus (approx. 60 cm)

Found it not in the field...., tried to find one but got only parts..

This one comes from an old collection from the 50th ore 60th and was now better prepared