THE MEDITERRANEAN LOWER CRETACEOUS

On the territory of Douar Raouraoua (Oued Riou valley), in a rather tectonized
section of the Sidi Seba Achir Formation, there are marls with intercalations
of micrograined limestones and boudinated clayey limestones, among which the
following Middle Aptian (Gargasian) ammonites were found: Acanthohoplites
slephanoides (Kas.), Colombiceras cf. crassicostatum (d'Orb.), Gargasiceras lautum
(Ant h.) and Pseudohaploceras akuschense (Ant h.).
The Formation is widespread in the Chouala area.
The Oued Fodda Clayey-Limestones Formation is revealed in scattered outcrops
near Oued Fodda dam, around Grand Pic, east of Djebel Ouarsensis, between Koudiat
Tifket and A. Hamichain, and around Kef Hala. Its sections are built of marls
and limestones, in some places with intercalations of argillites, dolomites and sandstones.
Stratigraphie volume: Tithonian-Aptian.
Berriasian fossils are found at Ain el Hadjella: Berriasella cf. calisto (d'Or b.).
Malbosiceras cf. malbosi (P i с t.), Pomeliceras (M.) paramimounum (M a z.), etc.
Among the limestones there occur many calpionellids as well.
At Oued Fodda dam: Berriasella calisto (d'O г b.) and Berriasella spp.
The Valanginian is proved by a number of ammonite finds (Ain el Hadjella)
along the road to the mines Sidi Abd el Kader, near Koudiat Tifket and A. Hamichain:
Thurmanniceras sp. indet., Kilianella sp. indet., Olcostephanus sp. indet.,
Valanginites sp., Neocomites neocomiensis (d'O r b.), etc.
The Hauterivian is not proved palaeontologically, but its development in the
continuous succession between the Valanginian and the Barremian is indisputable.
The Barremian is proved by Barremites sp., Silesites seranonis (d'O r b.), Eolytoceras
suhfimbriatum (d'O г b.), Heteroceras astieri (d'O r b.), etc., found at Oued
Fodda.
The Aptian comprises the upper part of the Oued Fodda Formation, built of
grey-green marls with intercalations of sandstones, limestones and clayey limestones,
while grey-black compact claystones appear in the upper part. The stage
is proved palaeontologically by Mattauer (1958).
The El Melaab Flyschoid Formation is widespread in the Tellian Atlas and
reaches up to 1700 m. It is built of alternation of dark-grey to black argillites, siltstones
and sandstones. Argillites predominate in the sections. Stratigraphie volume:
Aptian-Lower Albian.
Aptian fossils are found in the El Melaab Formation. At Ami Moussa, on the
eastern shore of Oued Riou: Ancyloceras ex gr. urbani (N e u m., U h 1.); at Oued
Lira: Parahoplites cf. uhligi A n t h.; west of Djebel Tafren: P. melchioris A n t h.
and Parahoplites sp. indet.; at OuedShifa: Acanthohoplites aff'. laticostatus S i n z.,
etc. Rich foraminifera associations are established.
Mattauer (1958) reports the Lower Albian Desmoceras latidorsatum
(M i с h.) at Kef Assaker.
The Redadoua Formation ("Formation marneuse de Redadoua") is built of
marls and calcareous argillites with limestone or dolomite concretions. Interbeds
of limestones and sandstones are observed in some places. The Formation is very
widespread in the Ouarsenis area, where it covers and / or replaces the EI Melaab
Formation and underlies the Hassi ben-Ziane Formation, with which it is connected
through lithological transitions. On the basis of foraminifera it is assumed
that this Formation comprises the Middle and Upper Albian Substages.
The Hassi ben-Ziane Formation ends the profile of the Lower Cretaceous in
Ouarsenis. It is represented by marls, clayey limestones and micrograined limestones,
and less frequently by dolomitized limestones. Intercalations of argillites, siltstones
and sandstones occur in some places. Marls predominate in the upper part
of the Formation, being with flint concretions in some places. Stratigraphie volume:
Upper Albian-Lower Cenomanian.
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