LIVERPOOL GEOLOGICAL ASSOCIATION.

January 8th, 1883.

At the Ordinary Meeting, held this date, at the Free Library, Mr. HENRY BRAMALL, M. INST., C.E., President, in the Chair, the following were elected Members:-Messrs. H. C. Bannister and W. H. Davies, Jun.

Proposed as Members :-Messrs. Frederick G. Clark, 47, Bickerton Street, Lark Lane; Henry Hall, H.M. Inspector of Mines, Rainhill; James E. A. Rogers, 7, Oak Terrace, Beech Street, Fairfield; William Hewitt, 21, Verulam Street; and H. F. Tildsley, 121, Queen's Road, Liverpool.

LIBRARY.

The President announced that the Council had arranged for the Library to be opened to Members, and had appointed Mr. ANTHONY W. AUDEN as Librarian.

DONATIONS.

Ramsay's "Geological Survey Memoir of North Wales," presented by Mr. Henry Bramall; Murby's Text Books, "Geology" and "Botany ;" sundry Botanical and other Diagrams, presented by Mr. F. P. Marrat.

COMMUNICATION.

Mr. ISAAC E. GEORGE drew attention to a Paper by Prof. Bonney in the Quart. Journ. Geol Soc. on some structures in Volcanic Rocks from North Wales, and exhibited specimens and rock- sections from the localities mentioned.

Abstract of the

DISCUSSION

On the Paper by Mr. HUGH F. HALL, F.G.S., read on December 4th, 1882, entitled

“SOME OBSERVATIONS ON THE DARWINIAN

THEORY OF EVOLUTION OF SPECIES."

Mr. THOMAS BRENNAN, in opening the discussion, remarked that, as Mr. Hall's Paper was still in the hands of the printer, many points which deserved careful attention would probably have been omitted from the notes which he had taken at the meeting. He divided the Paper into three parts.

(Vol. III- Session 1882-83-No. 4)

1st. Criticisms more applicable to the book than to the theory under consideration. 2nd. Facts which, according to the author, are opposed to the Evolution theory. It will be necessary to examine these latter at some length. 3rd. Theological arguments, which for many reasons, cannot well be discussed in a Scientific Society,

The criticisms may be summed up as follows:-A clear and precise definition of the term species is of the utmost importance in any discussion concerning their origin. Mr. Darwin has not given a definition; he says, on the contrary, that the term is undefinable, and, lastly, he has not given us the origin of species at all.

Surely when an author writes about something which he shows is indefinable, it is rather unreasonable to complain that he has not given us a definition. Our author, who the speaker supposed, believes species to be definable, is quite as remiss on the point as Mr. Darwin. Of course he admits that there are good and true species, but the only true test given us is that the offspring of distinct species are infertile. It is at once seen that this test is of no practical value outside the domain of our domestic animals and cultivated plants. Of its theoretical value he would speak presently. That Mr. Darwin does not give the precise origin of any species is a fact no more opposed to his theory than the omission to explain the origin of the solar system is adverse to the acceptance of Newton's discoveries; or that our inability to name the Teutonic ancestor of each English family inclines us to discredit the general belief in the Anglo-Saxon origin of a great part of our nation. The sterility of hybrids and the fertility of mongrels are the strongest arguments used by our author. It is here that the want of a clear definition of species is of importance, as when we point to the sterility of closely allied varieties, our opponents claim them as distinct species, and when we point to the fertility of distinct species, they claim that they were only varieties. So it will ever be. If it be a mark of distinct species that the offspring are infertile, hybrids will always be infertile. There is, however, another

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way in which we can try the validity of this test. There are two seaweeds, which we may denote as No. 1 and No. 2. If we fertilize No. 2 with the male element of No. 1, they are perfectly fertile, but if we cross No. 1 with the male element of No. 2, they are as perfectly sterile. By the only test which our author gives us, these are varieties and distinct species at the same time; or, in other words, this one species is two and these two are one. This test, then, like all others which have been attempted, fails to define this shadowy abstraction called "species."

Another difficulty brought forward by our author is that animals which become feral revert to the original type. There are very few cases in which we can say what was the original type. In the case of feral horse there should have been two original types, as those in America differ from those in Asia. Reversion is nevertheless an established fact, but followed out it proves too much for our opponents; horses are sometimes born with the "cross on the back" like the ass, and with stripes on the body and legs like the zebra and quagga, their parents being devoid of such markings. These we believe to be reversions to the original type which gave birth to the four species of equus.

The difficulty about double variations and rudimentary organs will vanish if our author will shake himself clear of the notion that species spring into existence exactly as we see them now. If he can carry his mind back to a time when the bird itself was in a rudimentary state, when the flower and the insect were less dependent upon each other than they are now, it will be easy for him to conceive that each would be as well fitted for the circumstances in which it lived as it is now.

Persistent types are not by any means unfavourable to the Evolution theory; there is no more reason why the original form should not live side by side with its modified descendants than there is that the London and North Western Railway Company should not have a line from here to London because they have branch lines to Bristol and Nottingham. The

lingula has existed from the Cambrian to the present time, the same fungus which lived on the Silurian corals is found fattening on the deep sea corals of the present day, showing that the law of continuity is as applicable to the organic world, as it is admitted to be to the inorganic; so far, therefore, they contradict the theory championed by our author. All theories have their difficulties, which, with our present knowledge we are unable to explain; Evolution is no exception to this rule, but we repudiate the idea that, because we are unable to explain them, they are incapable of explanation.

Our author, unless the speaker had misunderstood him, asserts that there are no facts in favour of the theory of Evolution. He did not wonder in that case at the author's surprise that scientific men have so universally accepted it. It was his duty, as leader of the discussion, to recall a few facts.

The speaker would appeal first to our own science, and he who runs may read the following facts in it. The great classes into which animals are divided make their appearance on the earth in the order in which they would do if the evolution theory were true; that is, the simplest organisms appear before the more complex ones; the lower orders of each class come in before the higher. As the animals become more complex the variations go on more and more rapidly, because an organism with twenty variable parts will present oppotunities for favourable varieties more numerously than one with only two such parts. Lastly, they become more and more like the animals now living, as we approach nearer to our own times.

We find nothing higher than the invertebrata throughout the vast thickness of the Laurentian, Cambrian and the greater part of the Silurian system. In these we find that the brachiopods precede the lamellibranchs, the tetrabranchiate cephalopods come in before the higher dibranchiate. The fishes of the Lower Ludlow beds are of a high order but Pandar has found some objects in the Lower Silurians of Russia which he believes to be the teeth of fishes allied to the Lampreys. More recent discoveries in the Carboniferous

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rocks of Canada have strengthened Pandar's determination of these conodonts; so the generalization holds good that the lower order precedes the higher. It is not till we reach the Carboniferous period that we find the amphibians, which are succeeded by true reptiles in the Permian rocks. The Permian period has been called an appendix to the Carboniferous, and we cannot but notice that the difference between the amphibians and the reptiles is very slight. In the Trias we meet with mammals for the first time, and, true to our generalization, they are of the marsupial order. Birds probably existed during the same period, but we have no positive proof of the fact. Marsupials continued throughout the Oolitic period, but not trace of them is found during the Cretaceous or the period represented by the great unconformity between the Cretaceous and the Eocene. This great gap in the history of the mammalia is but one out of many proofs of the imperfection of the geological record. During this period the marsupial mammals would, according to our theory, undergo rapid variations and specialization, and instead of wondering, as geologists did, twenty years ago, at the sudden appearance of such a varied fauna as the London and Paris basins reveal to us, we hold that it is just what we should expect when conditions favourable to the preservation of fossils occurred after such an interruption as that just pointed out.

The power of prediction which a theory gives is justly looked upon as the strongest proof that can be given of its truth, and it is to what may be termed the fulfilled predictions found in Mr. Darwin's book, that the almost universal acceptance of his theory may be attributed. To account for the wide difference between animals, Mr. Darwin was obliged to plead that the intermediate forms were lost, and he was met by the taunt that it was very easy to prove any theory by such pleading. I imagine that it is too late now to take up such a position, as the intermediate forms are no longer conjectural, but as much a part of our zoological chain as any living form. As if Mr. Darwin had the gift of prophecy, he singled out the birds as widely removed from the other classes of verte