Trilobites of Gees, Germany
  last revised 01 December 2007 by S.M. Gon III

Locality: Near Gerolstein, Eifel region, Rhine Valley, Rhenish Massif, Western Germany

Stratigraphy: Ahrdorf Formation,  Flesten-Member

Age: Early Middle Devonian (Middle Eifelian), 398 - 392 mya

The countryside at the Gees locality, western Germany
The site "Pelm-Salmer Weg" near the small village of Gees, in western Germany, is famous for fine Eifelian trilobites that have been found there over a 200 year period. The Trilobitenfelder (Trilobite Fields) there comprise the type stratum and locality for many classic trilobite species. The earliest trilobite described from the site dates back to 1825, when Heinrich Georg Bronn collected and described "Calymene schlotheimi," now Geesops schlotheimi. Other early descriptions include Gerastos cuvieri (Steininger 1831), Asteropyge punctata (Steininger 1831) and Ceratarges armatus (Goldfuss 1839). World famous pioneer trilobitologists Rudolf & Emma Richter contributed greatly to the knowledge of the trilobites from the Gees site and to trilobites in general, via an impressive number of publications. The site has been extremely popular to collectors, some of whom brought heavy equipment to dig there. In 1984 the situation became critical; the site looked like a cratered war zone. Authorities were forced to prohibit further collecting there. Today, the Gees site is protected.

Gees locality during the Devonian
Gees locality today

Among the most common trilobites from the Gees site are Geesops schlotheimi (by far the most common species of Gees, with ~90% of trilobite specimens collected there being G. schlotheimi), as well as Gerastos cuvieri, and Cyphaspis ceratophthalma. Very rare, but distinctive Gees taxa include Ceratarges armatus, Harpes macrocephalus, Radiaspis radiata, and Astycoryphe senckenbergiana.  The preservation of exoskeleton at Gees is often very good, with dark exoskeleton contrasting against lighter matrix, as in the examples below. The best preserved sometimes show a wood-like "grain" that is a signature of trilobites from the area.

Geesops schlotheimi
(Bronn 1825)
Family Phacopidae
Cyphaspis ceratophthalma
(Goldfuss 1843)

Family Aulacopleuridae
Ceratarges armatus
(Goldfuss 1839)
Family Lichidae
Harpes macrocephalus
Goldfuss 1839
Family Harpetidae
Scutellum geesense
Gerastos Cornu Kettneraspis elliptica
Scutellum geesense
(Richter & Richter 1956)
Family Styginidae
Gerastos cuvieri
(Steininger, 1831)
Family Aulacopleuridae
Cornuproetus cornutus
(Goldfuss 1843)
Family Aulacopleuridae
Kettneraspis elliptica
(Burmeister, 1843)
Family Odontopleuridae

The site is extremely diverse in trilobites, and as is often the case in Devonian sites, the constituent orders are Phacopida, Corynexochida (Styginidae), Proetida,Lichida, Odontopleurida, and Harpetida. Here is a complete list of Gees trilobite species: 



Order Corynexochida
Suborder Illaenina
Family Styginidae
Scutellum geesense Richter & Richter, 1956
Scutellum flabelliferum (Goldfuss, 1839)
Thysanopeltella (Thysanopeltella) acanthopeltis (Barrande, 1852)
Scabriscutellum scabrum (Goldfuss, 1843)
Order Phacopida
Suborder Phacopina
Superfamily Acastoidea
Family Acastidae
Neometacanthus stellifer (Steininger, 1843)
Asteropyge punctata (Steininger, 1831)
Superfamily Phacopoidea
Family Phacopidae
Phacops imitator Struve, 1970
Phacops fragosus Struve, 1970
Geesops schlotheimi (Bronn, 1825)
Pedinopariops brongniarti (Steininger, 1831)
Order Proetida
Superfamily Proetoidea
Family Proetidae
Gerastos cuvieri (Steininger, 1831)
Dohmiella chamaeleo (Richter & Richter, 1918)
Family Tropidocoryphidae
Astycoryphe senckenbergiana Richter & Richter, 1919
Cornuproetus (Diademaproetus) menzeni Kowalski, 1975
Cornuproetus (Cornuproetus) cornutus cornutus (Goldfuss, 1843)
Tropidocoryphe barroisi (Maillieux, 1904)
Superfamily Aulacopleuroidea
Family Aulacopleuridae
Cyphaspis ranuncula (Erben, 1953)
Cyphaspis ceratophthalma (Goldfuss, 1843)
Cyphaspis balanops (Erben, 1953)

Order Harpetida
Family Harpetidae
Harpes macrocephalus Goldfuss, 1839

Order Lichida
Superfamily Lichoidea
Family Lichidae
Ceratarges armatus (Goldfuss, 1839)

Order Odontopleurida
Superfamily Odontopleuroidea
Family Odontopleuridae
Radiaspis radiata (Goldfuss, 1843)
Radiaspis comes (Basse, 1998)
Kettneraspis elliptica (Burmeister, 1843)
Eifliarges caudimirus (Richter & Richter, 1917)
Koneprusia lukiana Rückert & Klever, 2007

Gerastos cuvieri (Steininger, 1831)
Many thanks to Benedikt Magrean and Harald Prescher, who provided references, images, and information in the development of this page. It certainly would not have been developed without their great help!
Also thanks to Andreas Rückert, who provided excellent images of additional Gees trilobites, including Kettneraspis and Scutellum, to round out the display!

Some Gees references:

Harald Prescher's excellent website on Devonian trilobites of the Eifel Region

Basse, M., 2003. Eifel-Trilobiten 2. Phacopida 1. Goldschneck-Verlag, Korb.


Kowalski, H., 1990. Trilobiten aus dem Devon der Eifel. Aufschluss, 33:11-63.


Richter, R., 1909. Beiträge zur Kenntnis devonischer Trilobiten aus dem Rheinischen Schiefergebirge. Marburg.


Struve, W., 1970. Beiträge zur Kenntnis der Phacopina (Trilobita), 7: Phacops-Arten aus dem Rheinischen Devon. I. Senckenbergiana lethaea, 51(2/3):133-189.

Related locality: Hunsruck, Germany
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