Fossils from Geisingen

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I've been visiting the sporadically operated clay pit in Geisingen a.d. Donau since 2001. For those who don't know the way: Take the Geisingen exit from the A81. Drive through the town and take a left at the street after the last roundabout and then immediately right onto the road which runs parallel to the autobahn. After roughly 1 kilometer the clay pit can be seen on the left.


Stratigraphy and Fossils
The southern part of the pit is of main interest, since the fossiliferous layers of the Geisingen-Oolith of the upper Aalenian are regularly exposed there, or at least until recently. The border between the murchisonae and the concavum zones is to be found in this 40-70cm-thick block layer made up of iron oolith bearing limestone. Argillaceous shale full of concretions covers this layer and above that is the Conglomerate Bank which builds the transition to the Bajocian stage. Here one finds mostly bivalves and belemnites along with the occasional badly preserved ammonites. On top of that is the fossil-free Wedelsandstein, which builds the top of the exposure in the clay pit.
Over the years a lot of collectors, including myself, were able to collect a good amount of well-preserved fossils, sometimes with their shells still intact. I heard great tales from other collectors about the golden days and managed to learn more and more about the geological situation as time went on. Some highlights for me were a Brasilia decipiens with a circumference of 45 cm, a number of well-preserved Hammatoceratidae, some ichthyosaur vertebrae and a partial jaw from the crocodile Steneosaurus sp. The regular finds of Brasilia, Graphoceras, bivalves, belemnites and the occasional sea urchin rounded things off.


The present situation (2009)
The clay pit was still in full operation in 2001. At that time it belonged to the Breisgauer Portland Cement Co., which delivered the clay to its nearby cement plant to be mixed under the limestone which was won at the quarry on the other side of the autobahn. New portions of the Geisingen Oolith were regularly exposed and regular visits for collectors were always worthwhile. A few years later, however, the entire complex was taken over by Holcim, whose policy at the time was to shut down the competition, which is exactly what it did in Geisingen. It wasn't long before the cement plant lay in ruins, the work in the quarry was cut back radically and material was only moved occasionally in the clay pit. It was still possible to find fossils, but you had to do a lot of work beforehand.
Since then there's been a lot of talk about recultivating and creating a biotope, but those were just rumors. I decided to get to the bottom of things and have found out the following information. The clay pit and quarry are now run by the Geisinger Kalkstein Schotterwerk GmbH & Co. KG. The works manager has told me that yes, partial recultivation shall be taking place in the future, but that clay shall still be sporadically removed from the pit, which means that as long as collecting is still tolerated, it may still be worthwhile to try your luck here.

I'll close off now by showing some of my finds.



Graphoceras sp. (Buckman 1898), 6 cm. Cut and polished.



Graphoceras cf. concavum (Sowerby 1815), 13 cm.
Brasilia bradfordensis (Buckman 1881), 20 cm.
Brasilia decipiens (Buckman 1881), 19 cm.
Eudmetoceras aff. eudmetum (Buckman 1920), 17 cm.
Brasilia aff. bradfordensis (Buckman 1881), 10 cm.
Graphoceras decorum (Buckman 1904), 8 cm.
Graphoceras (Ludwigella) cornu (Buckman 1887), 5,5 cm.
?Brasilia (Paqueria) flocossa (Buckman 1899), 11 cm.
Bredyia or Hammatoceras diadematoides (Mayer 1871), 4 cm.
Ichthyosaurus sp. (Koenig 1816) 6 cm, vertebra.
Pleurotomaria armata (Muenster 1844), 4 cm.
Bathrotomaria amyntas (D'Orbigny 1856)?, 4 cm.
Pressastarte sp. (Zakharov 1970), 3,5 cm.
Pholadomya murchisonae (Sowerby 1827), 7 cm.
Nautilus Cenoceras sp. (Hyatt 1844), 14 cm.
A couple of cut and polished pieces:
Cenoceras intermedius, 18 cm.
Brasilia sp.
Roger Furze
Update January 2014
More than 4 years have passed since I wrote this article and since then pretty well nothing has changed at the pit. No more clay has been removed, and the plants are beginning to take over again. Now it really looks like an inoperative pit. As far as I know, collecting is still tolerated, but it's an incredible grind freeing up the Oolith in the hopes that something worth saving is to be found in the few blocks that you've managed to lever out after a whole day's work. The waste tip has been so worked through over the years that it's hardly worth a look any more.
Well anyway, I did manage to find some more nice stuff in the years in between which I'll show below along with a few older finds, but I don't think I'll be going back there that often any more.
A388a.1 kopie
Parammatoceras sp. (Sepkoski 2002), 14,5 cm.
A544a.1 kopie
Graphoceras ?fallax (Buckman 1888), 7,5 cm.
A120a.1 kopie
Graphoceras (Lucya) cavatum (Buckman 1902), 17 cm.
A34.1 kopie
Graphoceras (Ludwigella) rudis (Buckman 1889), 3,5 cm.
E18a.1 kopie
Galeropygus sublaevis (McCoy 1848), 5 cm.
Be35.1 kopie
Megateuthis elliptica (Miller 1826), 25 cm.
L49b.1 kopie
Cucculaea sp. (Lamarck 1801), 6,5 cm.
L72.1 kopie
Ctenostreon sp. (Eichwald 1862), 14 x 12,5 cm.
L220a.1 kopie
Grammatodon sp. (Meek 1860), 7 cm.
R6a.1 kopie
Cast of a partial jaw of Steneosaurus sp. (St.Hilaire 1825), 14 cm long. The original is at the geological institute in Tuebingen.
Further reading
Furze, Havlik & Aiglstorfer (2010): Die Tongrube Geisingen: Fenster in den Mitteljura der Westalb, in: Fossilien, Heft 2/10.

Gründel, Ebert & Furze (2011): Die Gastropoden aus dem oberen Aalenium von Geisingen (Süddeutschland), in: Zitteliana 51, S. 99-114.