EXPLANATION OF THE PLATES AND WOOD-CUTS. 



The simple curve of the septa and concave front distinguish this Nautilus. 

 Fig. 7. Nautilus subsulcatus, var. {N. subsulcattis, Phill. Geol. Yorks. ii. 9,^2, in part.) 

 This appears to be the same species as the Hmestone specimen figured by Prof. 

 Philhps ; but as it has a shorter aperture, we have thought best to distinguish it as 

 a variety. That author refers to Coalbrook Dale as one of the localities of his 

 species, so probably he had seen the shell before us. 

 Fig. 8. Nautilus armatus. Discoid, strongly ribbed, ribs elevated into tubercles ; 

 septa numerous. 



Diameter of the shell about 2i inches. 



There is only just enough preserved of this shell to show that the septa are en- 

 tire, and that the ribs almost form spines ; it much resembles Ammonites armatus 

 of the Lias. 

 Fig. 9. Nautilus falcatus. Discoid, inner whorls exposed ; the front convex ; sides 

 nearly flat ; the outer edge of each whorl obtusely angular, the inner edge inclined 

 towards the preceding whorl, the space between crossed by many arched ribs ; 

 septa simply concave; siphuncle central; aperture nearly square, but 6-sided, 

 with two of the sides very small. 



Length of the aperture 1 inch. 



Diameter of the shell about 2f inches. 

 Fig. 10. Bellerophon hiulcus, var. [B. hiulcus, Fleming's British Animals, 338.) This 

 differs from the specimens found in the mountain-limestone (M.C. t. 470. f. 1.), 

 in having indistinct concentric striae crossing those which are parallel to the lines 

 of growth, and in all the striae being sharper. 

 Fig. 11. Bellerophon Navicula. Globose, expanded, keeled, and flattened on each 

 side of the keel, smooth ; columella solid, produced ; whorls rapidly increasing. 



Diameter 5^ Hues. 



The form of the aperture resembles the section of a boat, whence the name. 



Plate XLL 



Remains of insects and fishes : p. 440. 

 Engraved by Mr. James de Carle Sowerby. 

 Fig. 1 to 4. Limulus anthrax. This fossil is considered by Dr. Milne Edwards to be 



a new species of Limulus. 

 Fig. 1 represents a nearly perfect specimen, with two of the legs extending from under 



the body : in figures 2 and 3 the shield is believed to have been separated ; but 



Dr. Milne Edwards states that it is difficult to account for the three short horns 



exhibited by each specimen : figure 4 is a detached shield. 

 Fig. 5 to 7. Liynulus rotundatus. This fossil is also considered by Dr. Milne Edwards 



to be a new species of Limulus. 

 Fig. 6 is the counterpart of figure 5. The membrane connecting the spines, and the 



circular outline of the animal, are considered to be peculiar. 

 Fig. 8. Limulus trilobitoides. (Buckland.) 



Fig. 9. Apus dubius. The only living animal to which Dr. Milne Edwards could refer 



1 



