We now close the long record of Ancient Life, during which whole races and families departed, and others took their place the march of vitality being ever forward to higher and higher orders. We have seen that all the great types of life-radiate, molluscan, articulate, and vertebrate had their beginning simultaneously and independently on the globe, and that all subsequent progress has been restricted to the modification and elimination of these primal patterns. We have seen the graptolites of Siluria rise, culminate, and depart with that period; seen also its curious encrinites and foot-stalked sea-urchins, or cystidea, flourish and die within the same limits; and witnessed its wonderful flush of trilobite life, which waned in the old red, and finally disappeared about the middle of the carboniferous era. So also have we witnessed the larger crustacean forms of eurypterus and pterygotus come strongly and forcibly on the Devonian stage, and somewhat speedily wane and die out with the coal period, during which other forms, prefigurative as it were of the existing limulus, take their places. In like manner the curious bone-clad fishes of the old red (the "palichthyan" aspect of fish life) rise and depart with that system-only a few of the genera, but none of the species, living into the carboniferous epoch. And when we come to the coal period itself, there also all the wonderful and exuberant forms of its vegetation-its stigmaria, sigillaria, lepidodendra, bothrodendra, calamites, and tree-ferns-start into being, flourish in profusion, and depart with those physical peculiarities which stamped glaciers of the Vosges, Wales, Ireland, and the Highlands of Scotland; or like many stones in the pleistocene drifts. 4. A hardened cementing mass of red marl, in which the stones are very thickly scattered, and which in some respects may be compared to a red boulder-clay, in so far that both contain angular, flat-sided, and striated stones, such as form the breccias wherever they occur.-Journal of Geological Society, vol. xi.

their impress on the life of that era. So also with its sauroid fishes; and so also with many genera and species of its shell-fish and corals and encrinites, which though more lowly are nevertheless peculiarly distinctive of carboniferous seas, and are never found in the waters of subsequent ages.

From the first to the last-from the Silurian to the Permian-all has been growth and decay, and in that death a progress which ever goes forward without halt or hesitation. No indecision; no trial-work; no error to be corrected; no blunder to be revised. And yet amid all this incoming and outgoing, as we shall see in the following chapter, there has been no break in vitality, no change of the great primal patterns, but merely such modifications as best harmonise with the new conditions of each succeeding era. Nor must we regard this harmony between geographical condition and organic manifestation in any other light than that of a mere co-adaptation; for over and above it there is clearly a prescient design, having respect to development in time from more general to more specialised types, and from physiological simplicity to physiological complexity of functions. From the obscure and simple forms of the lowest stratified systems we rise stage after stage to higher and higher manifestations of life; onwards and still upwards is the orderly course of creation; and yet in this vast and varied progression every member is bound to that which preceded it, as well as to that which accompanies it, by the ties and relationship of one great cosmical plan. This is surely more than mere 'physical development”—something higher than the "transmutation of specific forms under the force of external conditions"—something more precise and definite than "natural selection in the struggle for existence," or any other of the materialistic hypotheses

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that have been recently advanced to account for the great chronological elimination of vitality. It is (if anything man shall ever comprehend) the gradual unfolding of a predestined scheme-a divine conception, to the realisation of which the various forces of nature, co-related and coadapted, are in ever-active co-operation.

THE MIDDLE PAST.

MESOZOIC SYSTEMS-THE TRIAS, OOLITE, AND CHALK.

We now take leave of the palæozoic aspects of the world, and pass on to those of the Mesozoic or "middle life" period-characterised by forms and species which hold an intermediate place between those of the more ancient and those of the more modern epochs. The grand primeval types and patterns are still the same-radiate, molluscan, articulate, and vertebrate-but the modifications of the types are new, and the consequent organisation higher and more complex. The "differentiation" of the vital functions (as zoologists express it) now becomes more marked and apparent-that is, instead of organisations in which several functions are performed by the same organ, each function has an organ specially devoted to its purpose. The expression of Creative thought has become more specialised, and the plants and animals of the newer epochs bear the impress of that specialisation, and find in new external conditions a fitting habitat for their growth and elimination.

We now take farewell of the graptolites, cystideans, trilobites, and eurypterites of Silurian seas of the gigantic crustaceans and bone-cased fishes of the old red sandstone -of the sigillariæ, stigmariæ, lepidodendra, and other endogenous forms of the coal period-of the cup-in-cup, honey

comb, chain-pore, spider-web, and other corals of the Devonian and mountain limestones of the huge reptile-like fishes that swarmed in carboniferous waters; and are introduced to other species and newer forms of vitality. The vegetation that adorns the lands of the mesozoic period bears a closer resemblance and affinity to the tree-ferns, cycads, zamias, palms, and subtropical pines of the present day; and the botanist feels he can now institute comparisons with some prospect of success, and attempt restorations with greater confidence and certainty. So also in the animal world the approximations are becoming closer and closer; the divergence from existing families is less perceptible even to the unscientific observer; and the zoologist now meets with all the great divisions of vertebrate life— fishes, reptiles, birds, and mammals. A vast progress has been made in the great onward evolution of vitalitywhole families of lower life have died out, and higher ones have taken their places-and orders only beginning to come into existence in the primeval world are now approaching their culmination, or point of greatest numbers, variety, and development.

Besides these gradational advances from lower to higher forms, which are common to every geological epoch, there are also some curious external characteristics which must arrest the notice even of the least scientific and the least geological of observers. So noticeable are these features, that if the fossils of the palæozoic cycle were arranged on one side of a museum, and those of the neozoic on another, the difference would strike the casual observer as strongly as would the difference between the brute-man sculptures of the Ninevites and Egyptians on the one hand, and the man-god sculptures of the Greeks and Romans on the other. It is like passing from the Assyrian and Egyptian chambers of the British Museum to those devoted to the Greeks and