Arkell.1956.Jurassic..

222 THE IBERIAN PENINSULA
flank (Ariege) and near the west end of the range. In these areas there
are basalt flows and volcanic tuffs interbedded in poorly fossiliferous
dolomites and limestones attributed to the Lower Hettangian. The rocks
are without doubt Jurassic, for in the department of Ariege they overlie
Rhaetic lumachelles of Pteria contorta. (Dubar, 1925, pp. 215, 225;
1927, p. 587.)
The Lias is well developed and fossiliferous over the whole area, except
for the Hettangian and locally the Sinemurian, which are developed as
dolomites and poorly fossiliferous limestones. The Aalenian and Bajocian
are likewise complete, with all the NW. European faunas. The Upper
Jurassic is more sporadic in occurrence. The highest ammonite faunas
recorded are Oxfordian, but in parts of the Pyrenees there are thick
dolomites of Upper Jurassic age which pass up into Lower Cretaceous
limestones, and it is possible that the higher stages of the Upper Jurassic
will prove to be represented (Dubar, 1925, p. 252). In the Pyrenees of
Lerida there is a gap with unconformity between the Kimeridgian lithographic
limestones and Middle Jurassic dolomites without fossils (Dalloni,
1930, p. 170).
TITHONIAN
Borings near the south-western edge of the Aquitaine basin have
produced uppermost Jurassic and lowest Cretaceous micro-faunas, and
equivalent rocks are present also at outcrop on the north-west flank of the
range (Cuvillier & Debourle, 1954).
KIMERIDGIAN
On the south of the Pyrenees, near the east end, in the province of
Lerida, the lithographic limestones of Montsech contain a mixed land,
freshwater and sea fauna and flora, without marine mollusca or any other
invertebrates except insects. In facies the fauna resembles those of
Solnhofen in Franconia and Cerin in the Dept. of Ain, but the vertebrates
are held to indicate a somewhat lower horizon in the Kimeridgian
(Vidal, 1915; Broili, 1932). The thickness is estimated at 100 m. and
there is an unconformity and big gap below (Dalloni, 1930, pp. 163, 170).
UPPER OXFORDIAN
In the extreme west are up to 50 m. of poorly-fossiliferous calcareous
sandstones or greywackes attributed to the 'Lusitanian' and probably
Upper Oxfordian (Lamare, 1936, pp. 56, 178). On the Spanish side in
this western region Perisphinctes plicatilis (Sow.) and Ochetoceras canaliculatum
(v. Buch) have been recorded (Palacios, 1919^. 63); on the French
side in addition Euaspidoceras perarmatum (Sow.) and Taramelliceras
flexuosum Miinst. sp. (Dubar, 1925, p. 252).
LOWER OXFORDIAN
Black and grey limestones, 50-100 m., are probably attributable here,
but no distinctive ammonites are recorded (Lamare, 1936, pp. 56, 178).
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