Fig. 6 in New finds of skeletal fossils in the terminal Neoproterozoic of the Siberian Platform and Spain

Fig. 6. Microstructure of late Ediacaran and early Cambrian microfossils. A. Namacalathus hermanastes Grotzinger, Watters, and Knoll, 2000, Kuibis Subgroup, Nama Group, Upper Ediacaran, Zaris Subbasin, Namibia; MNHN Ca 370−1; A1, cross−section of stem; A2, detail of A1 showing blade−like elongate parallel crystals (laths) of calcite. B. Cribricyath Szecyathus cylindrucus Vologdin, 1957, Usa Formation, Botoman Stage, Lower Cambrian, Batenevskiy Range, Altay Sayan Foldbelt, Russia; MNHN Ca 194; B1, detail of skeleton outer wall; B2, detail of B1 (rectangle) showing microgranular microstructure. C. Cloudina hartmanae Germs, 1972, Birba Formation, Ara Group, Upper Ediacaran, Oman; MNHN Ca 361; C1, oblique longitudinal section; C2, detail of C1; C3, oblique longitudinal ultrathin section, crossed nicols. D. Cloudina hartmanae Germs, 1972, Birba Formation, Ara Group, Upper Ediacaran, Oman; MNHN Ca 360; D1, longitudinal section showing two primary skeletal layers; D2, detail of D1 showing secondary elongated crystals initiated at primary layer surface; D3, longitudinal ultrathin section showing several primary layers, crossed nicols; D4, detail of D3, transmitted light; D5, detail of D4, crossed nicols. Scale bars A1, B1, C1, D3 1 mm; A2, B2, C2, D1, D4 100 µm; C3, D2, D5 10 µm.