Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 14. 1989. (Budapest, 1989)
accept these names for the two biozones mentioned above, instead we suggest to retain the use of the Avisianum Zone and the Reitzi Zone, according to the following ideas. The Anisian/Ladinian sections of the Southern Alps were investigated in detail (RIEBER 1973, BRACK and RIEBER 1986). There an independent biozone occurs regularly above the Trinodosus Zone. RIEBER (1973) distinguished and named this one as "Polymorphus Zone", correlating it with ASSERETO's (1969) Avisianum Zone. Later on, KRYSTYN (1983) referred to the same interval designating his "Parakellnerites Zone". These three names are synonymous, of them the Avisianum Zone has the priority, so its further use is supported. The modern redefinition of the Reitzi Zone was done by BRACK and RIEBER (1986). They, listed the " Ceratites" elli pticus species group and the "reitzi" group (including reitzi, conspicuus, perauritus, ecarinatus , etc.) assigned to Nevadites by them, as characteristic forms of this zone. So the Reitzi Zone is equivalent to the informal "Nevadites Zone", above the Avisianum (="Polymorphus") Zone and below the Curionii Zone. Since such a modern and detailed study was not yet published on Balaton Highland sections, BRACK's and RIEBER 's opinion was accepted concerning the fossil content, time span and the position of the Reitzi Zone within the zonation. It must be mentioned however, that we are inclined to assign the species reitzi and conspicuus to the genus Xenoprotrachyceras , erected by WANG (1983). ~~ The other question is the setting of the Anisian/Ladinian boundary. BRACK and RIEBER (1986) drew this boundary above the Reitzi Zone, at the base of the Curinoii Zone characterized by the occurrence of "true" trachyceratids, bearing trachyceratid suture-line. This is the method introduced earlier in North America for practical reasons (see TOZER 1981, SILBERLING and NICHOLS 1982). In ideal case evolutionary events are used for delimitation of zones in the biostratigraphy. However, it is not a proper way to extend this principle to chronostratigraphy, so to the delimitation of stages. The occurrence of a higher taxonomic group is not a necessary criterion for drawing the boundary of a higher chronostratigraphic unit. (In this case the occurrence of the Trachycerataceae superfamily would mean the base of Ladinian, sensu BRACK and RIEBER). According to the principles of stratigraphy, a stage must be based on stratotype, its lower boundary must be drawn at the base of its lowermost chronozone/biozone per definitionem. The Ladinian has no designated stratotype section, but the type area is in the Southern Alps, where the lowermost formation is the "Buchenstein Beds" (BITTNER 1892), and the lowermost biozone is the Reitzi Zone (MOJSISOVICS 1882,), according to the original definitions. There is no reason for its modification. Consequently the zonation suggested and used by the present authors for the Upper Anisian/Lower Ladinian is the following: Curionii Zone Reitzi Zone Lower Ladinian Avisianum Zone Trinodosus Zone Upper Anisian The Vászoly section can be divided into four parts, according to the vertical distribution of ammonoid species (Fig. 4). Part A includes Beds 3/A-5. It is characterized by the presence of Stoppaniceras variabilis , which is accompanied by Longobardites zsigmondyi and Paraceratites ? sub- nodosus in the Beds 4-5. This assemblage reminds the " trinodosusfaunas" as well, but by the occurrence of species of Stoppaniceras it must be referred to the Avisianum Zone, according to RIEBER's (1973) data. Part B begins with Bed 5 (thus overlapping with Part A) by the occurrence of species of Parakellnerites. Beds 5 and 6 are characterized by P. frauenfelderi and P. sp., aff. felsoeoersensis , accompanied by Norites dieneri . Other species of Parakellnerites persist through the upper beds of the section.
