The activity of burrowing organisms seems to be of great importance in limiting the occurrence of stromatolites. Profiles of Callovian and lowermost Oxfordian of the Cracow-Wielun Upland, central and south Poland, are very useful for studies of relations between stromatolites and burrowing organisms. Many burrows, with up to 20 burrow apertures/sq m, of the Thallasinoides type occur in sandy crinoid limestones of early Callovian age. They are sublittoral deposits without stromatolites. However, stromatolites occur in stratigraphically condensed limestone sequences of middle and late Callovian age, and indicate deeper-water deposition. The associated fossils are pelagic forms: ammonites, belemnites, and coccoliths. Also present are iron-manganese nodules with a red or brow color. Probably these deposits accumulated on a submarine swell at a depth of several tens of meters. They pass laterally into deeper water marls which do not show any features of stratigraphic condensation. The latter deposits are without stromatolites, but contain numerous Zoophycos burrows.

Stromatolites of condensed sequences occur as beds of various thicknesses, up to 40 cm. Interstitia and pockets in stromatolites are filled by highly bioturbated red limestones. The limestones and marls above the stromatolites contain numerous burrow structures of the Chondrites type. Such relations suggest competition for space between blue-green algae and burrowing organisms. Probably the instability of the sediments caused by the activity of the burrowing organisms was an important factor limiting the spread of algal mats.

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