xiv INVERTEBRATE PALAEONTOLOGY 



FACING PAGE 



PLATE IV 40-41 



FIG. 



1. Orbiculoidea nitida. Coal Measures, Coalbrookdale. The 



glossy, largely chitinous, shell is perfectly preserved in an 

 ironstone nodule. 



2. Fragment of Pelecypod shell from the Upper Greensand, near 



Sidmouth, Devon, replaced by chalcedony in the form of 

 Beekite. 



3. Dactylioccras commune. Upper Lias, Whitby, Yorks. From a 



nodule of cement-stone. Complete and uncompressed 



4. Peronoceras annulatum (a closely similar species). Upper 



Lias, Runswick Bay, Yorks. From the shale, flattened and 

 telescoped. 



5. Cliona sp. Flint moulds of the crypts perforating the shell of 



Inoceramus. Upper Chalk, Sussex. 



6. Atrypa reticularis. Ludlow Limestone, West Knowle, Craven 



Arms, Salop. Internal mould (ventral side), showing 

 muscular and other impressions. 



PLATE V 40-41 



1. Lioctras cf. opaltnum. Bajocian, Burton Bradstock, Dorset. 



Internal mould showing sutures. 



2. Ammonite wholly encrusted by Pyrite and Marcasite. Oxford 



Clay, near Oxford. 



PLATE VI 42 



1. Part of a fossil-band in Upper Ludlow Flags, Onibury, Salop. 



The right-hand side was near the quarry-face, and solution 

 has reduced the organisms to casts and moulds. Farther in 

 (to the left of the figure) the shells are preserved intact. 

 " Orthis" lunata, Chonetes striatella and Camarotoechia sp. 

 are the chief forms present. 



2. Part of a fossil-band in Caradocian (Acton Scott beds), 



Marshbrook, Salop. Completely decalcified. " Orthis" 

 testudinaria and Tentaculites. 



