In the lower Jura formations (the lias of Lyme Regis), the ink bag of the sepia has been so wonderfully preserved, that the material, which myriads p 272 of years ago might have served the animal to conceal itself from its enemies, still yields the color with which its image may be drawn.*
[footnote] *A discovery made by Miss Mary Anning, who was likewise the discoverer of the coprolites of fish. These coprolites, and the excrements of the Ichthyosauri, have been found in such abundance in England (as, for instance, near Lyme Regis), that, according to Buckland's expression, they lie like potatoes scattered in the ground. See Buckland, 'Geology considered with reference to Natural Theology', vol. i., p. 188-202 and 305. With respect to the hope expressed by Hooke "to raise a chronology" from the mere study of broken and fossilized shells "and to state the interval of time wherein such or such castrophes and mutations have happened," see his 'Posthumous Works, Lecture', Feb. 29, 1688. [Still more wonderful is the preservation of the substance of the animal of certain Cephalopodes in the Oxford clay. In some specimens recently obtained, and described by Professor Owen, not only the ink bag, but the muscular mantle, the head, and its crown of arms, are all preserved in connection with the belemnite shell, while one specimen exhibits the large eyes and the funnel of the animal, and the remains of two fins, in addition to the shell and the ink bag. See Ansted's 'Ancient World', p. 147.] — Tr.
In other strata, again, nothing remains but the faint impression of a muscle shell; but even this, if it belong to a main dividion of mollusca,* may serve to show the traveler, in some distant land, the nature of the rock in which it is found, and the organic remains with which it is associated.
[footnote] *Leop. von Buch, in the 'Abhandlungen der Akad. der Wiss. zu Berlin in dem Jahr' 1837, s. 64.
Its discovery gives the history of the country in which it occurs.
The analytic study of primitive animal and vegetable life has taken a double direction: the one is purely morphological, and embraces, especially, the natural history and physiology of organisms, filling up the chasms in the series of still living species by the fossil structures of the primitive world. The second is more specially geognostic, considering fossil remains in their relations to the superposition and relative age of the sedimentary formations. The former has long predominated over the latter, and an imperfect and superficial comparison of fossil remains with existing species has led to errors, which may still be traced in the extraordinary names applied to certain natural bodies. It was sought to identify all fossil species with those still extant in the same manner as, in the sixteenth century, men were led by false analogies to compare the animals of the New Continent with those of the Old. Peter Camper, Sommering, and Blumenbach had the merit of being the first, by the scientific application of a more accurate p 273 comparative anatomy, to throw light on the osteological branch of palaeontology — the archaeology of organic life; but the actual geognostic views of the doctrine of fossil remains, the felicitous combination of the zoological character with the order of succession, and the relative ages of strata, are due to the labors of George Cuvier and Alexander Brongniart.
The ancient sedimentary formations and those of transition rocks exhibit, in the organic remains contained within them, a mixture of structures very variously situated on the scale of progressively-developed organisms. These strata contain but few plants, as, for instance, some species of Fuci, Lycopodiaceae which were probably arborescent, Equisetaceae, and tropical ferns; they present, however, a singular association of animal forms, consisting of Crustacea (trilobites with reticulated eyes, and Calymene), Brachiopoda ('Spirifer, Orthis'), elegant Sphaeronites, nearly allied to the Crinoidea,* Orthoceraitites, of the family of the Cephalopoda, corals, and, blended with these low organisms, fishes of the most singular forms, imbedded in the upper silurian formations.
[footnote] *Leop. von Buch, 'Gebirgsformationen von Russland', 1840, s. 24-50.
The family of the Cephalaspides, whose fragments of the species 'Pterichtys' were long held to be trilobites, belongs exclusively to the devonian period (the old red), manifesting, according to Agassiz, as peculiar a type among fishes as do the Ichthyosauri and Plesiosauri among reptiles.*
[footnote] *Agassiz, 'Monographie des Poissons Fossiles du vieux Gres Rouge', p. vi. and 4.