THE MEDITERRANEAN LOWER CRETACEOUS

The Hauterivian is discovered over considerable areas in the investigated strip,
where it is of typically neritic type: sandy limestones, marls, clayey limestones, sandstones,
organogenic limestones, among which there are: Rhynchonella irregularis
P i с t., R. lata d'Orb., R. multiformis (Roem.), Terebratula sella Sow.,
T. rusillensis L о г., T. acuta Q u e n s t., Neithea atava (Roe m.), Spondylus
roemeri D e a с h., Pholadomya gillieroni P i с t., Camp., Ostrea tuberculifera
(К о с h. - D u n k.), Natica bulimoides d'O r b., etc.
The Barremian and Aptian are represented by subreef and reef limestones with
rudists and Orbitolinidae. They are well exposed in the Gornac area — Suva Planina
mountain zone, Kucai-Svarlik zone, Tupijnica zone and in the Dobrodol-
Grlica zone. The following species have been found among them: Requienia ammonia
(Gold f.), R. lonsdalei (S о w.), R. pellati P a q., R. gryphioides Math.,
Toucasia, Monopleura, as well as various other bivalvs, gastropods, brachiopods
and echinids.
These sediments are traced to the southeast near Pirot and Dimitrovgrad, from
where they pass into Bulgarian territory. Paraurgonian terrigenous-carbonate
sediments are developed to the side of the Urgonian limestones.
The Albian is connected with two lithostratigraphic units: Lenovac Beds and
Jabukovac Beds.
The Lenovac Beds are found in the zone Tupijnica — Gamsigrad — GolubaS
hills. They are represented by sandstones and sandy marls among which there are
fossils characterizing the three substages of the Albian.
The Jabukovac Beds occur in Northeastern Serbia between Dolni Milanovac
and Negotin, reaching the Bulgarian frontier in the Kula region. Their lower part
is built of glauconitic limestones, breccia-like limestones, marls and sandy claystones
with Inoceramus and ammonites, whereas the upper part consists of marls,
claystones and sandstones of Cenomanian.
The faunistic composition of these sediments is analogous to that of the Albian
associations in Northwestern Bulgaria.
Two considerable depressions were formed in Eastern Serbia during the Early
Cretaceous, in one of which flysch was formed (Lujnica zone) and in the other one—•
volcanogenic-sedimentary formations (Kraina area of the Danubian trough).
The Lujnica zone is a continuation of the flysch trough of the Kraiste, which
is traced to the northwest of the western slopes of Suva Planina mountain. The flysch
sediments of the Berriasian and Valanginian are formed in this zone. In fact, there
exists exact proof only for the Berriasian, namely: Pseudosubplanites sp., Berriasella
(P.) picteti (Z i 11.), Fauriella gallica (M a z.), Calpionella elliptica С a d.,
C. alpina L о г., Tintinnopsella carpathica (M u г g., Fi 1.), etc.
In the Kraina area which comprises the western and central parts of the Danubian
trough according to G r u b i с (1975), there are volcanogenic-sedimentary
rocks which are described as "Vratarnica Series" comprising the base of the Lower
Cretaceous as well. Above them lie the Timok (or Sinaia) Beds. These are aleuritic
limestones, calcarenites, clayey limestones and marls (silicified in some places).
Diabases and diabase tuffs occur among these sediments, their partial analogue
being the Azuga Beds from the South Carpathians. The sediments contain only radiolaria.
In their upper part the Timok Beds are built of breccia-conglomerates with
calcareous cement, sandy limestones, calcarenites, siltstones, micrograined limestones
and marls.
The Timok Beds (Berriasian-Hauterivian) are exposed in the Miroc antiform,
in the Eastern Miroc syncline in the Kosovica zone, in the Negotian region
and on the Veliki Izvor Plateau.
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