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Plate XXVI. Triassic Reef Fabric

(A) Sphinctozoan segmented sponge with encrusting algae; facies MF-2 of Chap-
ter VIII. The sample MS-15 is from a Cipit block on the Rossz1ihne trail in the
Dolomites, at the Seiseralm, northern Italy. Similarity of the biota of these undo-
lomitized exotic blocks with that of the Ladinian Wetter stein Limestone of the
Northern Limestone Alps indicates that the blocks are derived from a reefy rim of
encrusting boundstone. This is similar to that seen around the rim of banks which
have been described in Austria and Bavaria by E. Ott (1966) and illustrated by
Fig. VlII-16. Thin section, x 11
(B) Spongiomorph hydrozoan from low in the Rhaetic Rotelwand bioherm,
south of Hallein, Austria. The bioherm occurs as an isolated mass in Kossen shale
basin but is capped by impressive organic encrusting boundstone. Sample RK-15
contains a framestone of Spongiomorpha encrusted with a fine tubular organism;
facies MF-1 of Chapter VIII. Such spongiomorph fabric, along with corals,
sponges, and red algae, makes up major boundstone reefs in the Triassic. Thin
section, x 6