The Tafna Basin corresponds to the lowlands, which are located in front of Tessala and Traras ranges, below the Tlemcen mountains, Algeria. This basin displays a complete sedimentary cycle dominated by lagoonal-fluvial and marine deposits. The continental formations located at the base of these deposits are mainly composed of alternating sandstones and clays. An early late Miocene age has been previously attributed to them, based on direct correlations with marine deposits. Search for micromammal fossils led to the discovery of three different rodent species from a single level of the Djebel Guetaf section, located at the bottom of these deposits. The rodent assemblage indicates a late Miocene age. Combined magnetostratigraphical and biostratigraphical investigations were carried out to provide a more accurate age control of these continental deposits. Sixty-four oriented rock samples were collected for a magnetostratigraphic study along a 92 meters thick section including the fossiliferous layer. Rock magnetic investigations indicate the presence of both high and low coercivity minerals. Specimens subjected to progressive thermal demagnetization procedures show that the samples exhibit a high temperature magnetization component and display a normal polarity. Based on biostratigraphic constraints, the Guetaf section is correlated with Chron C4An, indicating an age ranging from
9.1 to 8.7 Myr.
  

Mammal-bearing localities have been discovered in the marine and lacustrine series of the middle Ilerdian (Lowermost Eocene) from Southem France (Minervois and Corbières). In the localities of Fordones, Monze, Fournès, and La Gasque, thirty mammal species have been identified. Among others, they include ischyromyid rodents (Microparamys and Pseudoparamys), paromomyid and adapid primates (Arcius and Donrussellia), new insectivores, condylarths, and a dyspternine pantolestid. These faunas provide new informations on the early Eocene Mesogean faunas of Rians and Palette. The assemblages of primates and rodents from Fordones support good  correlations with Palette which was recently placed near the standard-level of Dormaal (MP 7). In fact, Palette and Fordones could be even older than Dormaal. Consequently, there seems to be a relatively important temporal gap between the late Paleocene of Cernay and the Sparnacian of Dormaal. This gap could be partly filled with the Mesogean faunas of Palette, Fordones, and Silveirinha. On the basis of these new mammal faunas the marine middle Ilerdian is proved to be older than the Cuisian stage of the Paris Basin. With regards to the position of the Fordones fauna at the top of the NP 10 calcareous nannoplankton biozone, the westem European paleomammalogists Paleocene/Eocene boundary could be situated between the NP 9 and NP 10 biozones.