FUNCTIONAL MORPHOLOGY AND PALEOECOLOGY OF MIDDLE CAMBRIAN ECHINODERMS FROM MARGINAL GONDWANA BASINS IN BOHEMIA

Bohemian Middle Cambrian marine sediments are exposed in two fault controled basins. The Pribram-Jince (P-J) basin contains a complete Middle Cambrian section; the Skryje-Tyrovice (S-T) basin contains strata comprising the Eccaparadoxides pusillus zone (Middle Middle Cambrian). Sediments in these basins were spasmodically deposited and commonly exhibit turbidity flow characteristics. There is no evidence for algal mats and bioturbation is rare. Echinoderms are varied and somewhat plentiful. In the P-J and S-T basins the edrioasteroid-like Stromatocystites pentangularis and the eocrinoid Lichenoides "priscus" are found in near shore, above wave base sediments. Their method(s) of attachment are problematic. In deeper water, but above wave base, the earliest stylophoran Ceratocystis is found. Below wave base in the P-J basin, various species of Akadocrinus occur, some nearly 10 cm in height, and with discoidal holdfasts. "Sediment sticking" Lichenoides priscus are found in situ or are aligned and lying flat from destablizing currents. A probable new species of Stromatocystites is common; rare forms such as Cigara dusli and the ctenocystiod Etoctenocystis bohemicus are also present. Deeper water shales in the T-S basin yield abundant specimens of Trochocystites and the rare eocriniod Luhocrinus. In the P-J basin the entire echinoderm sequence is repeated in the younger P. gracilis Zone due to renewed deepening. Occurrences of echinoderms broadly resemble those on the broad margins of coeval western North America. Conditions differ in that facies are more compact and the temperatures were considerably cooler. This narrow Bohemian window on to the Middle Cambrian suggests that the "agronomic revolution" took place at different times in different places.