multiplying into many genera, and swarming in countless myriads, as the Devonian ages wear on. Again, towards the termination of the latter appear the first reptiles, which, during the Carboniferous and Permian eras, reign as the master-existences of creation. But Palæozoic or ancient

life passes away, and the Mesozoic or Middle period is marked, not only by countless forms, all specifically, and many of them generically, new, but by another wholly unknown, either as genus or species, during all the past. The little marsupials and insectivora appear 'perfect, after their kind,' and yet only the harbingers of the great mammalian period which is yet to come. In the volume of Creation, as in that of Providence, God's designs are wrapt in profound mystery until their completion. And yet in each it would appear that He sends a prophetic messenger to prepare the way, in which the clear-sighted eye, intent to read His purposes, may discern some sign of the approaching future.

Before we proceed, we must here, on behalf of the unlearned, and therefore the more easily misled, most humbly venture to reclaim against the use, on the part of men of the very highest standing, of the loose and dubious phraseology in which they sometimes indulge, and which serves greatly to perplex, if not to lead to very erroneous conclusions.

'In respect to no one class of animals,' says Professor Owen, in his last Address to the British Association, 'has the manifestation of creative force been limited to one epoch of time.' This, translated into fact, can only mean that the vertebrate type had its representative in the fish of the earliest or Silurian epoch, and has continued to exist throughout all the epochs which succeeded it. But the

difficulty lies in the translation. For at first sight the conclusion is inevitable to the general reader, that not only the lowest class of vertebrate existence, but also man and the higher mammals, had been found from the beginning, and that the highest and the lowest forms of being were at all periods contemporary. No one surely would have a right to make such a prodigious stride in the line of inference, on the presumption of supposed evidence yet to come. Again, Sir Charles Lyell, in his supplement to the fifth edition of his Elementary Geology, says, in speaking of these same Purbeck beds quarried by Mr. Beckles, 'They afford the first positive proof as yet obtained of the co-existence of a varied fauna of the highest class of vertebrata with that ample development of reptile life which marks the periods. from the Trias to the Lower Cretaceous inclusive.' Are marsupials and insectivora the highest class of vertebrata? Where, then, do the great placental mammals,—where does man himself,-take rank?

It were surely to be desired that some stricter and more invariable form of phraseology were adopted, either in accordance with the divisions of Cuvier, or some analogous system, adherence to which would be clearly defined and understood. Why should not the words class, order, type, have as invariable a meaning as genera and species, which, having an application more limited, are seldom mistaken? We are aware that such terms are often used by the learned in an indefinite and translatable sense, just as to the learned in languages it may be a matter of indifference whether the written characters which convey information to them be Roman, Hebrew, or Chinese. But it should be remembered that there is a large class outside which

seeks to be addressed in a plain vernacular,—which asks, first of all, definiteness in the use of terms to which probably they have already sought to attach some fixed sense; and that it is not well to unship the rudder of their thought, and send them back to sea again.

older, and ten

The next point which demands attention in our short résumé is that great break between the Permian and Triassic systems, across which, as stated in the following pages, not a single species has found its way. Much attention has been given to the great Hallstad or St. Cassian -beds, which lie on the northern and southern declivities of the Austrian Alps. These beds belong to the Upper Trias, and they contain more genera common to Palæozoic and newer rocks than were formerly known. There are ten genera peculiarly Triassic, ten common to to newer strata. Among these, the most remarkable is the Orthoceras, which was before held to be altogether Paleozoic, but is here found associated with the Ammonites and Belemnites of the secondary period.1 The appearance of this, with a few other familiar forms, serves, in our imagination at least, to lessen the distance, and, in some small measure, to bridge over the chasm, between Paleozoic and Secondary life. And yet, considering the vast change which then passed over our planet,-that all specific forms died out, while new ones came to occupy their room,—the discovery of a few more connecting generic links in the rudimentary shell-alphabet, which serve but to show that in all changes the God of the past is likewise the God of the present, no more affects in reality this one great revolution,

1 See Sir Charles Lyell's Supplement for corroboration of the foregoing statements.

the completeness of which is marked by the very difficulty of finding, amid so much new and redundant life, a single identical specific variety, than the well-known existence of the Terebratula in the earliest, as well as in the existing seas, can efface the great ground-plan of successive geological eras.1 Nor does it explain the matter to say that geographical changes took place, bringing with them the denizens of different climates, and adapted for different modes of life. The same Almighty Power which now provides habitats and conditions suitable for the wants of his creatures, would doubtless have done so during all the past. Geographical changes are at all times indissolubly connected with changes in the conditions of being; and they serve, in so far, to explain the rule in the stated order of geological events, when a due proportion of extinct and of novel forms are found co-existent. But how can they explain the exception? A singular effect must have a singular cause. And when we find that there were changes relating to the world's inhabitants altogether singular and abnormal in their revolutionary character, we must infer that the medial causes of which the Creator made use were of a singular and abnormal character also. On this head the best-informed ought to speak with extreme diffidence. We can but imagine that there may have been a long, immeasurable period during which a subsidence, so to speak, took place in the creative energy, and during which all specific forms, one after another, died out,—the lull of a dying creation,— and then a renewal of the impulsive force from that Divine Spirit which brooded over the face of the earliest chaotic

1 See Terebratula, in Appendix. The extinct Terebratula is now called Rhynconella.

deep, producing geographical changes, more or less rapid, which should prepare the way for the next stage in our planetary existence,-its new framework, and its fresh burden of vital beings.

The other great break in the continuity of fossils, which occurs between the Chalk and the Tertiary, seems to be very much in the same condition with that of which we have just spoken. New connecting genera have been discovered, but still not a single identical species. Jukes, in his Manual, published at the end of last year, says,—' Near Maestricht, in Holland, the chalk, with flint, is covered by a kind of chalky rock, with grey flints, over which are loose yellowish limestones, sometimes almost made up of fossils.' Similar beds also occur at Saxoe in Denmark. Together with true cretaceous fossils, such as pecten and quadricostatus, these beds contain species of the genera Voluta, Fasciolaria, Cyprea, Oliva, etc. etc., several of which Genera are only found elsewhere in the Tertiary rocks.1

Sir Roderick Murchison's late explorations in the Highlands,—although, of course, local in their character,—have made a considerable change in the GEOLOGY OF Scotland. The next edition of the Old Red Sandstone will be the most fitting place to speak of these at length; and I have some reason to believe that Sir Roderick himself will then favour me with a communication giving some account of them. Suffice it at present to say, that the supposed Old Red Conglomerate of the Western Highlands, as laid down in the year 1827 by Sir Roderick himself, accompanied by Professor Sedgwick, and so far acquiesced in by my husband,

1 A doubt has nevertheless been expressed whether these are not broken-up Tertiaries.