Fig. 4 in Silicified Mississippian brachiopods from Muhua, southern China: Lingulids, craniids, strophomenids, productids, orthotetids, and orthids

Fig. 4. Different results of the silicification of brachiopod valves from the Muhua Formation. A. Subradial lamellae of silica arising along fibres of the secondary shell layer as seen on the external surface of shell. B. Net−like pattern formed by silica on the internal surface of the terebratulid valve reflecting the mosaic of the terminal faces of fibres (see text for further explanation). C. Punctate shell microstructure preserved on a silicified terebratulid valve. D. Spiriferoid ventral valve silicified with "spongy" silica; general view (D1) and enlargement (D2).