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Plate XXIV. Triassic Boundstones

(A) Late Triassic coralline reef with encrusting algal fabric. The framestone is of
coral stalks and bulbous, irregularly laminated forms, coarser than Tubiphytes;
facies MF-2 of Chapter VIII. Interstices are lined with the same stromatolitic
crinkly laminae with tiny tubules. Voids ultimately have been filled with coarse
centripetally oriented calcite. Sample SP3 is from the Steinplatte reef front near
Waidring, Austria (see Fig. VIII)2). Thin section, x 11

(B) Tubiphytes encrusting boundstone (bindstone) from the reefy front of the
Dolomite Middle Triassic banks; facies MF-l of Chapter VIII. Sample MS-4 is
from a Cipit (exotic) limestone block in the Rosszahne at the Seiseralm in north
Italy. Fabric is mainly encrusting laminated growths indistinguishable from much
of the Tubiphytes in the Permian of southwestern United States. Several cavities
are filled with drusy calcite but others are filled with silt-size detrital, contempora-
neous internal sediment. This is probably a typical "reef-margin" sediment of the
Dolomite carbonate banks. Thin section, x 9