thiolliericrinid crinoids from the lower cretaceous of crimea

— 627 —Fig. 1 —Localities of Thiolliericrinidae in the Crimea.Gisements à Thiolliericrinidae en Crimée.Chornaya Basin (1 - Kuchky, 2 - Rodnoie), Belbek valley (3 - Belbek, Kuibyshevo, 4 - Karatlykh, 5 - Chuku), 6 - Bairakly, 7 - Tass-Kor Ravin (Mramornoie), 8 - Beshterek, 9 - Mezhgorie, 10 - Tanass (Alekseevka and Krasnossiolovka).Thiolliericrinidae are found but extremely rarely inthese bioherms ;- 2 :« barrier » reefs. They have large volumes (upto 15 m thick and several hundred metres long), builtof big nodules of the calcareous algae and, rarely,colonial corals. Here, in the reef rocks, lenses of thecoarse-grained sandstones and « pockets » saturatedby the quartz pebble are frequent. One can note,among reef-dwellers (besides above mentioned oysters),Prohinnites, Trichites, Heterodiceras and alsonerineid gastropods and so on. The locality on theChuku Mountain is the example of such « barrier »reef. Rare columnals and calyxes of Heberticrinusheberti were found here ;- 3 : «tower-like » bioherms, are the intermediatetype between the two previous ones. They show a discoidshape with an average size (the height is not morethan 7-8 m with the diameter up to 15-20 m) the frameworkof these bodies is built by cloddy masses,consisting of skeletons of colonial hexacorals, hydrozoansand calcareous algae. The interstices betweenbodies of the reef-forming organisms are filled withloose calcareo-argillaceous masses. Therefore the characteristictube-like forms appear in the process ofweathering of these bioherms. Small oysters, brachiopods(Craniscus sp., Ismenia cf. perilustrus Sm ir ­n o v a and others), calcareous sponges, bryozoans,small solitary corals, serpulids and others organismsalso are among the reef-dwellers. Traces of boring