thiolliericrinid crinoids from the lower cretaceous of crimea

— 629 —They avoided settling on « yet-formed » bioherms,the height of which was not more than 2 m. Theremains of the crinoids under discussion are almostabsent on the bioherms placed in the limestoneshaving an arenaceous admixture or with then quartzouspebbles. Thiolliericrinidae avoided the bioherms,the main rock-forming component of whichwas the calcareous algae. Under the same conditions,the thiolliericrinid remains are more frequent on biohermshaving many interstices filled with the argillaceousmass. The finds of Thiolliericrinidae are accompanied,as a rule, by the finds of the bulb-like echinoidspines, the spiny asterozoan plates and the dactylatesponges.The remains of the Thiolliericrinidae are foundmore often in the inner, more loose core of a bioherm.However it does not mean that they are absenton the external walls. Moreover, rare columnals andthecae are also found outside the bioherm, in the surroundingrocks. But, in this case, they are oftenstrongly rounded. However, the remains of one speciesare found only in the bedded microphytolithiclimestones. This is Conoideocrinus conoideus.Heberticrinus heberti is a « background » specieseverywhere. But at almost every bioherm there is acharacteristic species, distributed locally. Such isThiolliericrinus belbekensis in the « Belbek » locality(see fig. 1 and table 1), Loriolicrinus asper on theKaratlykh M ountain, Heberticrinus irregularis in theRodnoie environs etc. However frequently H. hebertiis the species which only represents the family on abioherm.Occurrence of the Thiolliericrinidae in the BelbekValley was already published by Arendt (1974, p. 57),Arendt & Yanin (1964, p. 140).Towards the West of the Belbek River, in the ChornayaBasin (see « Rodnoie » in the table 1), theremains of the late Berriasian thiolliericrinids werefound in the paleofacies analogous to the describedabove. However, hydrozoans are the main reefbuildingorganisms here (personal communication ofI.Y. Bugrova), and rudists are usual among reefdwellers(Yanin 1985, p. 25). Besides, some columnalsof Thiolliericrinidae indet. were found in this region(see « Kuchky » on fig. 1 and in table 1) in the organogenouslimestones of the middle part of the Berriasianstage. These limestones are slightly arenaceousand built by crinoidal debris (various species of thegenus Apiocrinites, rarely « Isocrinus » arzierensis(De Loriol), calcareous sponges, oysters, corals(solitary and colonial forms), brachiopods (Rioultinarobusta Sm irno va, Symphythyris arguenensis Moisseev),serpulids etc.Conditions of the existence of Thiolliericrinidae inthe central and eastern Crimea are somewhat different.For example, in the Tass-Kor Ravin (« Mramornoie» - see table 1 and fig. 1), the Lower Berriasianclays occur on the washed out surface of the marbledTithonian limestones and contain small bioherms (thethickness is up to 1 m and the diameter is 2 to 3 m).The main reef-building organisms are various calcareoussponges. Solitary and colonial corals and calcareousalgae are scarce. The dwellers of these tiny reefsare small oysters, brachiopods, tubicolous worms andregular echinoids with large thorn-like spines. Crinoidsare rare. They же Apiocrinites sp., Eugeniacrinitessp. and Isocrinus sp. (only columnals). The stemjoints of Thiolliericrinidae are found here. Occurrenceof crinoids in the Berriasian deposits of theM ramornoie was published by Lyssenko & Vakhrushev(1974, p. 149).In the villages Alekseevka and Krasnossiolovka(« Tanass » - see fig. 1 and table 1), the Thiolliericrinidaeare found in the small bioherms among theLower Berriasian clays and sandstones, which occuron the washed out and extremely rough surface of theTithonian limestones. These bioherms form an almostunbroken horizon, but reach the greatest developmenlon the Tithonian substratum swells probablybeing the initial points of its forming. The biohermsare built by the rolled debris of the basement rocksand by the calcareous alga pellets. Among reefdwellers,there are rare corals, oysters, calcareoussponges, sea-urchins and sea-lilies (Thiolliericrinidaeindet. and Cyrtocrinida indet.).3 — TERMINOLOGYA special terminology, in regard to skeletal elementsof the Thiolliericrinidae, is used in the followingchapters. The principal designations are as below (fig.2).Ad - attachment (terminal disk) ;lAx - primaxillar (the axillar of the first brachialseries) ;IIAx - secondaxillar (the axillar of the second brachialseries) ;