NO. 12 SPENCE SHALE AND ITS FAUNA RESSER 25 



PAGE 

 Iphidclla grata, new species 4 



Figs. 14, 18. Ventral valves (X3). 



Figs. 15, 17. Molds of the exterior surface of dorsal valves (X2). 



Fig. 16. Dorsal valve (X 3). 

 Acrothcle affinis, new species 5 



Fig. 19. Ventral valve (X2). 



Fig. 20. Dorsal valve (X 1.5). 



Figs. 21, 22. Interiors (X2.5). 

 IJ'ijiiaiiclla nantcs (Walcott) 6 



Fig. 22,. Ventral valve (X2). 



Fig. 24. Dorsal valve (X 2). 



Fig. 25. Dorsal valve (X3). 



Fig. 26. Ventral valve (X 1.5). 

 W'uimncUa spencci (Walcott) 6 



Figs. 27, 28. Ventral valve and mold of exterior. 

 IViniancUa rara (Walcott) 6 



Fig. 29. Only specimen known. 

 Hyolithcs ornatcllus, new species 7 



Figs. 30, z^- Posterior surface (X2). 



Fig. 31. Anterior surface (X2). 

 "Orthotheca" sola, new species 7 



Fig. 3S- Round conical tube (X 2). 

 Selkirkia spencei, new species 4 



Figs. 34, 35. Several flattened tubes. 

 Hyolithcs cecrops Walcott 7 



Fig. 36. Posterior surface. 



Fig. 37. Specimen showing cameration. 



Fig. 38. Operculum. 

 Archaeocyathns ? 3 



Fig. 39. Sides of tubes shown in lower and "ends" turned toward 

 observer in upper portion (X 6 ) . 

 Moraiiia, sp. undet 3 



Fig. 40. Irregular ovate pieces of the alga. 

 Eocrinus longidactylus (Walcott) 3 



Fig. 41. Plate with the most common style of ornamentation (X 6). 



Fig. 42. Poorly preserved calyx with several attached arms (X 2.5). 



Plate 2 



J'istoia ? luinuta. new species 21 



Fig. I. Supposed cranidium (X 6). 



Fig. 2. The holotype pygidium (X6). 

 Utia curio Walcott 21 



Fig. 3. Dorsal view of cranidium (X2). 

 Zacanthoidcs scrratus, new species 10 



Fig. 4. Cranidium retaining left libragene (X 2). 



Fig. 5. Pygidium, with exfoliated spines (X2). 



Fig. 6. Holotype with pygidium and thorax (X2). 



