• The association of reduced-eyed and blind trilobites with predominantly necto-benthonic organ- isms characterizes the well oxygenated cephalopod realm of a moderately deep outer platform environment. Accumulations of shelly debris that do not exhibit any evidence of corrosion and size sorting might result from intermittently slow sedimentation rates rather than from physical transport.

• "In this area the latest Frasnian succession is characterized by the occurrence of two dark-grey hypoxic limestone levels of Kellwasser-Kalk facies, the Lower (LKW) and Upper (UKW) Kellwasser levels (Lazreq 1992). They are separated by 80 cm of intervening grey-beige oxic calcilutites assigned to the Late Palmatolepis rhenana Zone by Lazreq (1992, 1999). The trilobites were recovered in section “1” from two levels: the older is situated 13 cm above theLKW, the younger 18 cm below the base of the UKW (horizons “1A” and “1B” in Fig. 1B). The sample collected in section “2” corresponds to the younger fauna of section “1”. Associated conodonts recov- ered from matrix material of the trilobite-bearing rocks were determined by Catherine Girard and Gilbert Klapper as fol- lows: the lower trilobite horizon yields Palmatolepis hassi sensu stricto and Pa. bogartensis which indicates the lower part ofMNZone 13 (for correlation of conodont zonations, see Klapper and Becker 1999); the upper trilobite bearing horizon yields Pa. rhenana, Pa. boogaardi, abundant Pa. bogartensis, Ancyrognathus asymmetricus and Polygnathus webbi (but neither Pa. linguiformis nor An. ubiquitus were found), indi- cating correlation with the upper part of MN Zone 13. Trilobite debris of exclusively disarticulated exuviae is concentrated in thin layers within the biomicritic limestone, along with mass occurrences of conodonts, homoctenid tenta- culites and fewer manticoceratid goniatites, smooth brachio- pods and crinoid ossicles. The association of reduced-eyed and blind trilobites with predominantly necto-benthonic organ- isms characterizes the well oxygenated cephalopod realm of a moderately deep outer platform environment. Accumulations of shelly debris that do not exhibit any evidence of corrosion and size sorting might result from intermittently slow sedi- mentation rates rather than from physical transport.