On the shore at Lyme Regis, these Coprolites are so abundant, that they lie in some parts of the lias like potatoes scattered in the ground; still more common are they in the lias of the Estuary of the Severn, where they are
Society of London, 1829, (vol. iii. N. S. part i. p. 224, with three plates.)
"In variety of size and external form, the Coprolites resemble oblong pebbles or kidney-potatoes. They, for the most part, vary from two to four inches in length, and from one to two inches in diameter. Some few are much larger, and bear a due proportion to the gigantic calibre of the largest Ichthyosauri; others are small, and bear a similar ratio to the more infantile individuals of the same species, and to small fishes: some are flat and amorphous, as if the substance had been voided in a semifluid state; others are Battened by pressure of the shale. Their usual colour is ash-gray, sometimes interspersed with black, and sometimes wholly black. Their substance is of a compact earthy texture, resembling indurated clay, and having a conchoidal and glossy fracture. 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, Sharks, and Dog-fish. Some Coprolites, especially the small ones, show no traces at all of contortion.
The sections of these fœcal balls, (see Pl. 15, Figs. 4, and 6,) show their interior to be arranged in a folded plate, wrapped spirally round from the centre outwards, 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 animals. (See Pl. 15, Figs. 3, and 10 to 14.) Dispersed irregularly and abundantly throughout these petrified fœces, 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 græcum of hyænas. These scales are the hard bright scales of the Dapedimn 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 sufficienly 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."
