1853.] LYELL AND DAWSON REPTILE AND LAND SHELL, 63 



either have been washed in after death, or may, when creeping on 

 the surface, have fallen into the open pit caused by the decay of the 

 tree, or it may have crept into some crevice in the trunk before it was 

 finally buried in the mud and sand. The fragments of wood found with 

 the bones, when sliced, show a dense irregular cellular tissue, with 

 scalariform ducts, like those of Ferns. They therefore probably 

 belong to Sigillaria, and may be parts of the woody tissue of the 

 tree within which they were found. 



The other vegetable fossils contained in these beds, and the cir- 

 cumstances under which they grew and were entombed, will be fully 

 discussed in another communication to the Geological Society. 



DESCRIPTION OF PLATES II„ III., IV. 

 Plate II. 



Fig. 1. Parabatrachus CoLEi. Portionof skull; half tiat. size. 12, Post-frontal 

 bone; 21, maxillary ; 22, prem axillary ; 26, malar; 27, squamosal; 

 73, lacrymal. 



Fig. 2. Dendrerpeton Acadianum. Portion of lower jaw, with teeth ; nat. size. 



Fig. 3. Small tooth ; a, b, magnified ; c, nat. size. 



Fig. 4. Ease of larger tooth, magnified 2\ diam. 



Fig. 5. Cranial bone ; nat. size. 



Fig. 6. Iliac bone ; nat. size. 



Fig. 7. Humerus, with proximal extremity of the radius at a ; nat. size. 



Fig. 8. The bones of the pelvis and hind leg of the Menobranchus : a a, b b, the 

 two elements of the iliac bone. 



Plate III. 



Dendrerpeton Acadianum. 



Fig. 1. Rib bone; nat. size. 



Figs. 2 a, 2 b. Dermal scutes, magnified 3 diam. 



Fig. 3. Pharyngeal Q) teeth, and dermal scutes at a ; nat. size. 



Fig. 4, 5. Vertebrae of the smaller reptile; nat. size. 



Fig. 6. Single vertebra ; magnified 4 diam. 



Fig. 7. Single vertebra from a, fig. 5 ; magnified 4 diam. 



Fig. 8. Bone-ceUs from the iliac bone of the Dendrerpeton Acadianum, magnified 



440 diameters. 

 Fig. 9. Bone-cells from the vertebrae of the smaller reptile. 

 Fig. 10. Bone-cells from the recent Menobranchus. 



Plate IV. 



Fig. 1. Land Shell from the inteiior of fossil tree, nat. size. 



Fig. 2. , magnified 3 diam. 



Fig. 3. , side view, magnified 3 diam. 



Fig. 4. , magnified 8 diam. 



Fig. 5, , striae of the surface. liyr„ «io d'am 



Fig. 6. Recent Pupa Juniperi, ditto. J 



Fig. 7. Fossil Land Shell, section of part of, magnified 25 diam. 



Fig. 8. , microscopical structure of the same, showing hexagonal 



cells, magnified 500 diam. 

 Fig. 9. , section of a cWpping, with hexagonal cells 



Fif." 1 1! } ' tubuliferous structure. i ^^^^^ gSO 



Fig. 12. , prismatic structure. I diam. 



Fig. 13. Recent Pupa Juniperi, hexagonal cell-structure of. 



Fig. 14. , prismatic cell-structure of. J 



VOL. IX. PART I. F 



