The article follows on an earlier publication by the author devoted to the urban development of Małopolska under Boleslaus the Modest (Krasnowolski, 2004–2005, pp. 36–37, 38–39). At the same time, it expands the subject discussed by the author in another work several years ago (Krasnowolski, 2004). The period in question was actually a quarter of a century from 1279 to 1306. The first of these dates marks the start of the reign of Leszek the Black (Leszek Czarny), successor to Boleslaus the Modest (Bolesław Wstydliwy), and the latter — capture of Kraków by Ladislaus the Elbow–High (Władysława Łokietka), efficiently competing with the rulers of Bohemia and exploiting the death of Wenceslaus III of Bohemia (Wyrozumski, 1992, pp. 200–201). Urban development from the time can be considered continuation of the urban development policy of Boleslaus the Modest, yet at a lower dynamic, due to political instability.

Biostratigraphic analysis of calcareous nannofossils from the Pełczyska section in the Miechów Trough (southern Poland) has revealed that the entire section covers the lowermost Maastrichtian. The UC16bTP Tethyan subzone is designated based on the presence of Broinsonia parca constricta Hattner, Wind and Wise, 1980, reworked remains of Uniplanarius trifidus (Stradner) Hattner and Wise in Wind and Wise, 1983 and the simultaneous lack of Eiffellithus eximius (Stover) Perch-Nielsen, 1968. The studied section spans also the interval between the LO of Zeugrhabdotus praesigmoides Burnett, 1997 and the FO of Prediscosphaera mgayae Lees, 2007 (UC16 S3 Boreal subzone). Quantitative analysis of nannofossil assemblages has shown the dominance of cold water species (up to 50%), e.g., Micula decussata Vekshina, 1959, Prediscosphaera spp., Arkhangelskiella spp., Calculites obscurus (Deflandre) Prins and Sissingh in Sissingh, 1977 and Lucianorhabdus cayeuxii Deflandre, 1959. In the early Maastrichtian, the studied area was more influenced by cool water masses from the Boreal Province rather than by warm water from the Tethyan Province. The significant predominance of cold water taxa and the elevated presence of Prediscosphaera cretacea (Arkhangelsky) Gartner, 1968 also supports the hypothesis of climate cooling in the early Maastrichtian.