308 ON FOSSIL FISH-TEETH. 



a damasked appearance to the tooth. These lines seem to result from a 

 slight difference in the closeness of the tubular structure, resulting in 

 a difference of colour in the fossilized tooth. These different layers of 

 colour being worn down on the irregular surface of the tooth, thus shew 

 in curved lines like contours on a map. 



Found with the last. 



PI. XV., Figs. 9 and 10. represent a small tOoth, evidently totally 

 unworn'and young. I have not thought it desirable to distinguish it by 

 any name. It may possibly be the young form of C. Hunterianus. 



COPROLITES. 



PI. XV., Figs. 1 1 and 12 represent two specimens of Coprolites, 

 found along with these fish remains. They are enclosed in a thick 

 concretionary layer of the ferruginous clay, in which they occur, which 

 assumes the general form of the inclosed Coprolite. On breaking off 

 this outer coating the true form, and spiral structure, of the Coprolite 

 itself is seen within. They are composed of a white and powdery sub- 

 stance with some slight ferruginous stains. They still contain a large 

 amount of phosphates, and, if occurring in any quantity, would doubtless 

 prove a valuable manure. 



A piece of the rock in which these teeth are found, with several 

 pieces of bone cemented together in it, is shown in PI. svi.. Fig. 5. The 

 principal of these are large plates, hke some of the large bony plates of 

 the head. (? Saurian) There is also a vertebra, long and thin. Figs. 3, 6, 7 

 and 8 on the same plate (xvi.) represent other fragments of bone found in 

 the same beds. And I think there can be little doubt that the locality 

 from which these teeth and bones have been procured, will, on closer 

 examination, yield many more specimens and varieties, and in all proba- 

 bility many in better preservation, possibly even entire fish. 



It is much to be regretted that Mr. Hislop has not himself been able 

 to trace out the geological position, and relations of these rocks. The 



