Commune: Sobków (pow. jędrzejowski, woj. świętokrzyskie)

Framework element or context represented:
Ubiquitous marine Miocene fossils.

Primary geological/geomorphological interest:
Palaeontological site, palaeotopography.

Comparative assessment justification:
The richest Miocene fauna of marine invertebrates in Central Europe. Far-fame of the site since 1787; described i.a. by Sir R.I. Murchison.

Protection status and accessibility:
Protection proposed for a part of the site; accessibility free.

Character of site: Natural exposure over the cropland.

Area: 400 ha

Altitude: 245-275 m a.s.l.

Lithology: silts, clays

Discipline: Palaeobiology, Palaeoenvironment, Stratigraphy of Phanerozoic

Process Age: *all periods

Bedrock Age: Neogene, *all periods

Description of primary interest:
Middle Miocene (Badenian; Zone NN5-6, N8-9) marine sequence of Korytnica, world-famous due to its biotic content, developed in a terminal bay of dismembered rocky shores along southern slopes of the Holy Cross Mountains, Central Poland. Its main part, the Korytnica Clays (c. 40 m thick), transgressive upon pre-Miocene topography, yields organic communities typically of tropical/subtropical Indo/West-Pacific affinities. Highly diversified mollusk assemblages, the richest in the Miocene of Europe, comprise: gastropods (554 prosobranch species described, 41 new to science), bivalves (c. 100 species, 1 new), chitons (15 species, 5 new), scaphopods (13 species, 4 new), and one cuttlefish. Prominent associates are: coelenterates (hydrozoans, corals, sea-pens), polychaetes (25 taxa, 9 species new), cheilostome and ctenostome bryozoans, inarticulate and articulate brachiopods (1 species new), stomatopod and decapod crustaceans, thoracican and acrothoracican cirripedes (2 species new), free-living crinoids (1 species new), other echinoderms, and ubiquitous microfossils of various kinds. The vertebrates are mainly teleost fish (otoliths - 105 taxa of 47 families, 3 species new) and diverse elasmobranchs (sharks and rays). The ubiquity of extremely well preserved fossils allows to study diverse relationships between species and their aut- and syn-ecological requirements, controlled by environmental conditions prevailing in the bay having been gradually shallowed by clay accumulation up to sea level. Overlying are Heterostegina Sands with huge oysters Crassostrea gryphoides (SCHLOTHEIM) and large pinnid Atrina radwanski JAKUBOWSKI, finally capped by red-algal beds.


ACTA GEOLOGICA POLONICA–Special Issues: vol. 27(2) of 1977, Vol. 29(3) of 1979, Vol. 34(3/4) of 1984; Supplementary Issue: Vol. 37(3/4) of 1987, Vol. 41(1/2) of 1991, Vol. 47(3/4) of 1997 - 43 monographic descriptions altogether.     BAŁUK W. (Lower Tortonian versus Badenian) gastropods from Korytnica, Poland - Part 1, Palaeont. Pol. 32 of 1975; Part 2, Acta Geol. Pol. 45(3/4) of 1995; Part 3, Acta Geol. Pol. 47(1/2) of 1997; Part 4, Acta Geol. Pol. 53(1) of 2003; Part 5, Acta Geol. Pol. 55(4) of 2005.     BAŁUK W. & RADWAŃSKI A. 1977–Organic communities and facies development of the Korytnica basin (Middle Miocene; Holy Cross Mountains, Central Poland). Acta Geol. Pol. 27 (2): 85-123.     BAŁUK W. & RADWAŃSKI A. 1996–Stomatopod predation upon gastropods from the Korytnica Basin, and from other classical Miocene localities in Europe. Acta Geol. Pol. 46 (3/4): 279-304.     HOFFMAN A. 1987–Literaturbericht; Korytnica Basin (Middle Miocene, Central Poland) and its communities. Zbl. Geol. Paläont. II, 1986: 265-269.     RADWAŃSKA U. 1992–Fish otoliths in the Middle Miocene (Badenian) deposits of southern Poland. Acta Geol. Pol. 42 (3/4): 141-328.     RADWAŃSKA U. 1994–Tube-dwelling polychaetes from the Korytnica Basin (Middle Miocene;Holy Cros Mountains, Central Poland). Acta Geol. Pol. 44 (1/2): 35-81.     RADWAŃSKA U. 1994–A new group of fossils: Middle Miocene (Badenian) opercular caps (calottae) of the tube-dwelling polychaetes Vermiliopsis, Saint-Joseph, 1894. Acta Geol. Pol. 44 (1/2): 83-96.     RADWAŃSKI A. 1969–Lower Tortonian transgression onto the southern slopes of the Holy Cross Mts. Acta Geol. Pol., 19(1): 1-164.