Fig. 11

Details of skeletal architecture of Labechia conferta (Lonsdale) in thin section, from the Much Wenlock Limestone Formation, middle Silurian of Wren’s Nest, Dudley, England, to show comparison with Labechia carbonaria in Figs. 7, 8, 9; enlargements from the sample illustrated in Fig. 10. a & b Transverse sections showing pillars and cyst plates in ppl (a) and xpl (b). The structure is composed of micritic skeletal material (compact microstructure). Red and orange arrows show the same pillars in each view, revealing a faint concentric structure, similar to L. carbonaria in Fig. 8b. c & d Vertical section showing three pillars, and half a pillar on the left side in ppl (c) and xpl (d). Short cyst plates connect the pillars and partly merge with them. The compact microstructure also includes a curved cone-in-cone fabric that was not observed in L. carbonaria, plus a fibrous architecture of upwardly diverging indistinct crystals, similar to L. carbonaria in Fig. 8a. Xpl views show partial overprinting of the structure by diagenesis, particularly well-shown in b (top-left and top-right pillars are partly extinct in multiple calcite crystals, and bottom centre pillar fully extinct in one calcite crystal) and in d (right hand pillar). In b and d, the xpl view accentuates the cone-in-cone and chevron architecture. Sample from Sedgwick Museum, Cambridge, UK, number X.50347.187