Morphometric attributes of 705 stromatoporoid specimens from a number of exposures from the Silurian of Podolia (Ukraine) and the Devonian of the Holy Cross Mountains (Poland), representing a wide array of shallow water carbonate sedimentary environments, have been analysed. Taken into account were such parameters as: general shape of the skeleton, shape of the final growth form (living surface profile), upper surface character, latilaminae arrangement, burial ratio and type of initial surface. A number of new ratios has been introduced, designed mainly to improve the mapping of the outlines of the stromatoporoids upper surfaces. All studied specimens were treated as belonging to one group, and relations between particular attributes were tested. The results were analysed in terms of potential environmental factors influencing stromatoporoid morphometric features. Most of the distinguished attributes are common in the studied group and occur in various combinations, with an important exception of parameters designed to reflect the shape of the skeleton’s upper surface, which are distinctly predominated by convex variants. This indicates that surface concavity was a highly undesired feature among stromatoporoids. Upper surface convexity is interpreted herein as a response to the hazard of clogging of the animals pores by tiny sediment particles suspended in the bottom turbid water layer. Common low burial ratios of final living surface profiles and the occurrence of specimens with a smooth upper surface but a non-enveloping latilaminae arrangement are other reflections of this phenomenon. Burial by sediments and redeposition were also important factors governing stromatoporoid development. No direct arguments indicating photosensitivity of stromatoporoids can be deduced from the presented results. The hitherto postulated allometric tendency among stromatoporoids of starting growth as laminar forms and later adopting consecutively higher profile shapes has not been confirmed here. On the contrary, a tendency for gradual elimination of very high profile forms with increasing stromatoporoid size has been observed. The final shape of a stromatoporoid skeleton was always an effect of a combination of various agents.

The Lower Jurassic to Aalenian carbonate-clastic Dudziniec Formation exposed in the autochthonous unit of the Tatra Mountains (Kościeliska Valley) hosts neptunian dykes filled with various deposits. The development of the fissures took place in multiple stages, with the same fractures opening several times, as is indicated by their architecture, occurrence of internal breccias and arrangement of the infilling sediments. Various types of internal deposits were derived in a different manner and from different sources. Fine carbonate sediments, represented by variously coloured pelitic limestones, calcilutites and fine calcarenites, most probably come from uplifted and corroded carbonate massifs (possibly from the allochthonous units of the High-Tatric succession). Products of weathering, both in dissolved form and as small particles, were washed into the sedimentary basin of the autochthonous unit, and redeposited within the dykes. The sandy varieties of the infillings, represented by red, ferruginous calcareous sandstones, come directly from the host rocks or from loose sediments present on the sea bottom at the time of fracturing. The most probable age of the infilling sediments is Sinemurian to Pliensbachian. The occurrence of dykes of this age is yet another feature confirming that the sedimentary development of the Lower Jurassic sandy-carbonate facies in the autochthonous unit was strongly influenced by synsedimentary tectonic activity, such as block-faulting.

This contribution presents the record of an abundant assemblage of well-preserved, thallophytic noncalcified algae and of an epibiotic form that has been recognised as a putative graptolite from the upper Silurian (Ludlow, Gorstian–Ludfordian) of Podolia (western part of Ukraine). The sediments represent a shallow peritidal zone of the shelf. A new genus and species, Voronocladus dryganti, belonging to the Dasycladales Pascher, 1931, is established. Most of the specimens representing the algal thallus are overgrown by problematical epibiotic graptolites, described as Podoliagraptus algaeoides gen. et sp. nov. This phenomenon is explained as an epiphytic mode of life of the putative graptolite on algae, and is herein compared to recently known coexistences of algae with other organisms. The excellent state of preservation, and the abundance of studied Dasycladales algae and epibiotic problematics indicate that the investigated mudstone layer can be treated as a ‘Konservat Lagerstätte’ sensu Seilacher (1970).