we may well be allowed to doubt the second. I affirm, then, that the Stonesfield Marsupials are phenomena unexplained by the theory of development; that their genealogical line is broken; and that they have no true organic base to rest upon. Are we to talk of "modest steps" as we advance towards the theory of development, while at every moment we are taking immodest strides which carry us out of the bounds of the natural world? To make the theory probable we must seek for some evidence that widely differs from that which is offered by the organic forms of our Secondary series. At the very lowest estimate of all the evidence derived from the organic remains of the Secondary rocks, we may affirm that it suggests not to any sober mind the theory of development. The conclusion might be pushed much farther; but, for the present, I am content to leave it here.

7. Organic Remains of the Tertiary Division, &c.

It now remains for me to notice the third and highest Division of our great geological deposits-including all groups of regular strata posterior to the Chalk, and anterior to the modern, or historic period. These deposits, which are of great aggregate thickness, and are extended over wide surfaces of all our Continents, admit of three primary subdivisions-Eocene-Miocene-and Pliocene and these three names imply, that in the lowest subdivision (Eocene) we find only the dawn of living Species-that in the next subdivision, living Species, though more abundant than before, still form

the minority-and, lastly, that in the upper subdivision (Pliocene) extinct Species decline in number, and living Species form the majority. In a certain sense this grouping is artificial, but it is based on observed facts; and since it was first published by Sir C. Lyell, has generally passed current among Geologists: and it now forms the basis of more complicated subdivisions, made necessary by the progress of discovery.

To describe these deposits is not my object; but I may add the following short notice of them.(1) They were preceded by great continental movements and changes of marine level; from which it follows, that they are not, as a general rule, co-ordinate with the rocks on which they rest, or form any structural passage into them. (2) They generally seem to mark the commencement of new physical conditions. (3) They were elaborated during a long period of ages and during very different conditions of temperature. Thus, the fauna of the Eocene period invariably indicates a sub-tropical temperature; while the fauna of some of our upper Tertiary beds indicates a climate in temperature apparently below that of England. (4) The passage from one subdivision to another is not always gradual, but more frequently seems to mark some sudden change of conditions. (5) The upper Tertiary groups give us no well-defined links, whereby we may connect them with the deposits of the modern, or historic period in which we trace the works of man.

As we ascend from one Tertiary group to another we find little difficulty in the interpretation of nature's

record but when we attempt to rise still higher on the scale, so as to connect the past with the present, we meet with documents so mutilated, and written in characters so obscure, that we almost despair of interpreting them, so as to draw from them any true, connected history. While making this attempt, we encounter continual indications of shifting marine levels— we find marine terraces high upon our mountain-sides, and raised sea-beaches far above any modern coastline-we find proofs of a long period when glaciers filled our high valleys, and when great masses of rock were drifted across the country on icebergs, and sometimes perched on our mountain-tops-and we find proofs of diluvial currents, which, descending from higher to lower levels, dragged with them enormous masses of gravel and superficial rubbish containing broken specimens of Mammal's bones and abraded fragments of all the older strata. To rationalize and arrange in historical order phenomena such as these, is perhaps the hardest task that has yet been submitted to Geologists*.

Leaving then all questions that are strictly geological, I will next consider the organic phenomena of the Tertiary division; and I will commence my task with

* This task has been attempted in a great original Memoir by Professor E. Forbes, (Memoirs of the Geological Survey of Great Britain, Vol. 1.) If he has not succeeded in clearing away all difficulties, and if some of his positions be considered doubtful, or untenable-it must, at least, be admitted, that he has brought, with no common skill, a vast mass of facts to bear upon the very difficult questions discussed, and that he has the undisputed honour of having taken the first firm steps towards a right conclusion.

a long extract from the Edinburgh Review, because it gives a condensed account of some of the leading facts that bear on the true development of organic life; and, still more, because it has formed the subject of some comments to which I must reply.

"On the theory of development, 'the stages of advance are in all cases very small-from species to species, and the phenomena, as shewn in the pages of geology, are always of a simple and modest character.' Let us test these assumptions by one single step from the Chalk to the London-clay, or any other Tertiary deposit. Among the millions of organic forms, from Corals up to Mammals, of the London and Paris basins, we find hardly so much as one single Secondary species. The humble Infusoria have been already noticed; and in the south of France it is said that two or three Secondary species straggle into the Tertiary system; but they form a rare, and almost evanescent exception to the general rule. Organic nature is once more on a new pattern-plants as well as animals are changed. It might seem as if we had been transported to a new planet; for neither in the arrangement of the Genera and Species, nor in their affinities with the types of an older world, is there the shadow of any approach to a regular plan of organic development. Our limits forbid us to enter on details, and in truth they are unnecessary; for if the chain of development be made of broken links, and if its first links were never bound to nature, (and we have proved already that they were not,) then must the last links inevitably want all

semblance of material support. But to convey to our readers some notion of the flora and fauna of the oldest subdivision of this new period, we may tell them in a few words, that we find in it the remains of a noble flora-coniferous trees, palm-trees, and thousands of drifted seed-vessels of very many new Species, but all of a tropical or sub-tropical type. To these we may add more than a thousand Molluscs, all new, yet making an approach to the types of living nature; and with them are two or three modern Species. We find Crocodilians greatly differing from the Secondary types, and conforming to the modern, yet not specifically agreeing with them-Serpents approaching the great Boa-Tortoises and Turtles in great abundance, but of extinct Genera-Fishes of the same general structure with the newer Families of the Chalk, but of different Species, and along with them at least two Families of a new type-Birds of nearly all the living Families, but the Species probably different. And lastly, we find a noble series of Mammals-especially Pachyderms; but including Carnivora, Quadrumana, and other Orders. Among the Mammals described by Cuvier from this lowest division of the Tertiary system, all the species are of extinct Genera. Some exceptions to this rule may have been found since; but, at least, all are of extinct Species. These different Orders and Classes are not arranged on any ascending scale. Carnivora are as old as Pachyderms, so far at least as we have any evidence bearing on the question; and Quadrumana (monkeys) are found in this division-thus contra