Prof. BucKLAND on Coprolites. 225 



largest Ichthyosauri*; others are small, and bear a similar ratio to the more 

 infantine individuals of the same species, and to small fishesf : some are flat 

 and amorphous, as if the substance had been voided in a semifluid state];; 

 others are flattened by pressure of the shale. Their usual colour is ash-grey, 

 sometimes interspersed with black, and sometimes wholly black. Their sub- 

 stance is of a compact earthy texture, resembling indurated clay, and having 

 a conchoidal and glossy fracture. Their general appearance will be best un- 

 derstood by referring to the figures given of them in Plates XXVIII. XXIX. 

 & XXX. The structure of the Coprolites at Lyme Regis is, in most cases, 

 tortuous, but the number of coils is very unequal; the most common number 

 is three : the greatest I have seen is six§: these variations may depend on the 

 various species of animals from which they are derived : I find analogous 

 variations in the tortuous intestines of modern skates, and sharks, and dog- 

 fish ||. Some Coprolites, especially the small ones, show no traces at all of con- 

 tortion or any other structured. 



The sections of these fffical balls show their interior to be arranged in a 

 folded plate, wrapped spirally round from the centre outwards, somewhat like 

 the whorls of a turbinated shell** ; their exterior also retains the corrugations 

 and minute impressions, which, in their plastic state, they may have received 

 from the intestines of the living animalsff. Dispersed irregularly and abun- 

 dantly throughout these petrified faeces are the scales, and occasionally the 

 teeth and bones, of fishes, that seem to have passed undigested through the 

 bodies of the Saurians, just as the enamel of teeth and sometimes fragments 

 of bone are found undigested both in the recent and fossil album grgecum of 

 hyaenas. These scales are the hard bright scales of the Dapedium politum, 

 and other fishes which abound in the lias, and which thus appear to have 

 formed no small portion of the food of the Saurians. The bones are chiefly 

 vertebrae of fishes and of small Ichthyosauri ; the latter are less frequent than 

 the bones of fishes, but still are sufficiently numerous to show that these 

 monsters of the ancient deep, like many of their successors in our modern 

 oceans, may have devoured the small and weaker individuals of their own 

 species. One large Coprolite ;{;| contains a vertebra, more than an inch in 

 diameter, of an Ichthyosaurus that must have been at least four feet in length : 

 and the jaws of large Ichthyosauri in the coflection of the Geological Society, 

 show how competent they were to swallow animals even of much greater size 



* Plate XXIX. figs. 1. 2. & 4. f Plate XXX. fig. 6-12. J Plate XXX. fig. 5. 



§ Plate XXVIII. figs. 3. 5. 11. 12'. |1 Plate XXXI. figs. 19. 20. 21. 22. 



H Plate XXX. fig. 4. & fig. 6—12. ** Plate XXVIII. figs. 3. 4. 10. 11. & 12'. 



tt Plate XXVIII. figs. 6. 7. 8. 9. +J Plate XXIX. fig. 2. 



VOL. III. SECOND SERIES. 2 G 



