Pl. 1, Fig. 49), a large Ranatra, and several Coleoptera.

Numerous fossil Insects have recently been discovered in the Tertiary Gypsum of Fresh-water formation at Aix, in Provence. M. Marcel de Serres speaks of sixty-two Genera, chiefly of the Orders Diptera, Hemiptera, and Coleoptera ; and Mr. Curtis refers all the specimens he has seen from Aix to European forms, and most of them to existing Genera.* Insects occur also in the tertiary Brown coal of Orsberg on the Rhine.

General Conclusions.

We have seen from the examples cited in the last four sections, that all of the four existing great Classes of the grand Division of Articulated animals, viz. Annelidans, Crustaceans, Arachnidans, and Insects, and many of their Orders, had entered on their respective functions in the natural world, at the early Epoch of the Transition Formations. We find evidences of change in the Families of these Orders, at several periods of the Secondary and Tertiary series, very distant from one another; and we further find each Family variously represented during different intervals by Genera, some of which are known

* See Edinburgh New Phil. Journ. Oct. 1829.

only in a fossil state, whilst others (and these chiefly in the lower Classes,) have extended through all geological Eras unto the present time.

On these facts we may found conclusions which are of great importance in the investigation of the physical history of the Earth. If the existing Classes, Orders, and Families of marine and terrestrial Articulated animals have thus pervaded various geological epochs, since life began upon our planet, we may infer that the state of the Land and Waters, and also of the Atmosphere, during all these Epochs, was not so widely different from their actual condition as many geologists have supposed. We also learn that throughout all these epochs and stages of change, the correlative Functions of the successive Representatives of the animal and vegetable kingdoms have ever been the same as at the present moment; and thus we connect the entire series of past and present forms of organized beings, as parts of one stupendously grand, and consistent, and harmonious Whole.

CHAPTER XVII.

Proofs of Design in the Structure of Fossil
Radiated Animals, or Zoophytes.

THE same difficulties which we have felt in selecting from other grand Divisions of the animal kingdom, subjects of comparison between the extinct and living forms of their respective Classes, Orders, and Families, embarrass our choice also from the last Division that remains for consideration. Volumes might be filled with descriptions of fossil species of those beautiful genera of Radiated Animals, whose living representatives crowd the waters of our present seas.

The result of all comparisons between the living and fossil species of these families would be, that the latter differ almost always in species, and often in genus, from those which actually exist; but that all are so similarly constructed on one and the same general Type, and show such perfect Unity of Design throughout the infinitely varied modifications, under which they now perform, and ever have performed the functions allotted to them, that we can find no explanation of such otherwise mysterious Uniformity, than by referring it to the agency of one and the same Creative Intelligence.

SECTION I.

FOSSIL ECHINODERMS.

THE animals that compose this highest Class in the grand division of Radiated animals, viz. Echinidans, Stelleridans, and Crinoïdeans, have, till lately, been considered as made up of many similar parts disposed like Rays around a com

mon centre.

Mr. Agassiz has recently shewn, (London and Edin. Phil. Mag. Nov. 1834, p. 369), that they do not partake of this character, from which the division of radiated animals is named; but that their rays are dissimilar, and not always connected with an uniform centre; and that a bilateral symmetry, analogous to that of the more perfect classes of animals, exists throughout the families of Echini, Asteriæ, and Crinoidea.

ECHINIDANS AND STELLERIDANS.

The History of the fossil species of Echinidans and Stelleridans has been most beautifully illustrated, in the plates of the Petrefacten of Prof. Goldfuss. Though derived from Strata of various degrees of high antiquity, they are for the most part referred by him to existing Genera.

The family of Echinidans appears to have ex

tended through all Formations, from the Epoch of the Transition series to the present time.*

No fossil Stelleridans have yet been noticed in strata more ancient than the Muschel-kalk.

As the structure of the fossil species of both these families is so nearly identical with that of existing Echini, and Star-fishes, I shall confine my observations respecting fossil animals in the class of Echinoderms to a family which is of rare occurrence, excepting in a fossil state, and which seems to have prevailed most abundantly in the most ancient fossiliferous formations.

CRINOIDEANS.

Among the fossil families of the Radiated division of animals, the Geologist discovers one whose living analogues are seldom seen, and whose vast numerical extent and extraordinary beauty entitle it to peculiar consideration.

Successions of strata, each many feet in thickness, and many miles in extent, are often half made up of the calcareous skeletons of Encrinites. The Entrochal Marble of Derbyshire, and the Black rock in the cliffs of Carboniferous

I found many years ago fossil Echinidans in the Carboniferous limestone of Ireland, near Donegal, they are however rare in the Transition formation, become more frequent in the Muschel-kalk and Lias, and abound throughout the Oolitic and Cretaceous formations.