Argiles d'lignite du Soissonnais
# Argiles d'lignite du Soissonnais

The Argiles d'lignite du Soissonnais is a geologic formation in the Oise department of northern France. The formation has provided fossil mammals, reptiles and fish as well as arthropods in the amber of the formation. The Argiles d'lignite du Soissonnais dates back to the Ypresian stage of the Eocene period.

## Description

The formation comprises a succession of lenticular bodies showing two main facies; clayey sands rich in frequently pyritised lignite, together with amber and grey clayey sands with less lignite (1 to 12 % of the sediment), with continental vertebrate fauna. These facies, the rarity of mollusk shells and charophytes, probably due to decarbonatation and the presence of pyrrhotite $(FeS_4),$ reflect a hypoxic environment.

The strata were deposited at the bottom of two channels cutting into underlying Thanetian marine green sands. The channels prograde toward the northeast and were discovered under Oise River Quaternary deposits.

## Fossil content

The formation has provided among others the following fossils:

### Mammals

**Primates**

* Teilhardina aff. belgica
* Cantius sp.
* Platychoerops sp.

**Artiodactyls**

* Diacodexis sp.

**Cimolesta**

* Esthonyx sp.
* cf. Apatotheria indet.

**Eutheria**

* Palaeosinopa sp.
* cf. Landenodon sp.

**Ferae**

* Dormaalocyon latouri
* Gracilocyon solei
* Oxyaena woutersi
* Palaeonictis gigantea
* Palaeanodon sp.
* Vassacyon taxidiotis

**Hyaenodonta**

* Arfia gingerichi
* Prototomus girardoti
* P. minimus

**Macroscelidea**

* cf. Macrocranion sp.

**Multituberculata**

* Multituberculata indet.

**Perissodactyls**

* Chowliia europea
* cf. Pachynolophus sp.

**Placentalia**

* Hyopsodus sp.

**Rodents**

* Pliolophus quesnoyensis
* Ischyromyidae indet.

**Soricomorpha**

* Leptacodon sp.
* Wyonycteris sp.

**Theriiformes**

* Peratherium sp.
* Pantodonta indet.

### Reptiles

**Turtles**

* Merovemys ploegi
* Paleotrionyx cf. vittatus
* Cryptodira indet.
* Trionychidae indet.

**Crocodiles**

* Allognathosuchus sp.
* Asiatosuchus sp.
* Diplocynodon sp.

**Lizards**

* Eolacerta sp.
* Placosaurus sp.
* Plesiolacerta sp.
* Gekkonidae indet.
* Lacertidae indet.
* ?Anguinae indet.
* ?Cordylidae indet.
* ?Iguanidae indet.
* ?Necrosaurus indet.

**Snakes**

* Dunnophis matronensis
* Saniwa cf. orsmaelensis
* Boidae indet.

### Amphibians

* Caudata indet.
* Pelobatidae indet.
* Salamandroidea indet.
* cf. Koaliella indet.

### Fish

* Anomotodon novus
* Isurolamna inflata
* Lepisosteus fimbriatus
* Otodus obliquus
* Pachygaleus lefevrei
* Palaeogaleus vincenti
* Palaeohypotodus rutoti
* Squalus orpiensis
* Striatolamia striata
* Cyclurus sp.
* Heterodontus sp.
* Myliobatis sp.
* Notorynchus sp.
* Squatina sp.
* Percoidei indet.

### Arthropods

**Diptera**

* Eurodoliopteryx inexpectatus
* Coleoptera, Hemiptera, Hymenoptera, Psocodea, Arachnida

### Pancrustacea

* Collembola indet.
* Hexapoda indet.

### Flora

* Nitellopsis sp.
* Pinophyta indet.
* Arecaceae indet.
* Myricaceae indet.
* Juglandaceae indet.
* Lauraceae indet.
* Apocynaceae indet.
* Caesalpiniaceae indet.
* Celastraceae indet.
