Fig. 9

Skeletal architecture of Labechia carbonaria in vertical thin section, selecting the margin of the section where the hand-ground thin section is thinner than the rest of the section. a & b Paired photographs in xpl (a) and ppl (b) revealing that the skeletal structure in b has been overprinted by sparitic calcite that crosses into space between skeletal elements and demonstrates that the skeletal structure is recrystallised. c & d Paired photographs in xpl (c) and ppl (d) showing enlargement of the centre-left part of a & b The overprinting by recrystallisation of sparite, crossing through the skeleton into intra-skeletal spaces is highlighted in four places by paired coloured arrows; note that these four are only examples, in fact the entire structure is recrystallised, which a ubiquitous feature of Palaeozoic stromatoporoids, see Discussion. Sample number NHMUK PI S 10490$1; Photos taken by the authors