that it required a duration all but eternal to deposit and build up this system alone. As an example of the high organizations found in this System of Rocks we here give a cut of the Eurypterus.

Having traversed this stupendous this stupendous system, and reached a date whose distance from the fair face of the extant creation is immeasurable, let us again halt

for review and examination of the fossil inhabitants which it entombs. Shall not our Development Theory now, if ever, find support and confirmation? In the estimation of the more moderate Evolutionists, twentyfive millions of years would scarce suffice to carry us back to the base of the Upper Silurian, while it would

equire millions more, thirty-five millions more, according to Mr. Croll, to bring us to the base of the Lower Silurian, where we now stand.* Shall we not here, then, if ever, discover decisive evidence of animal organizations degenerating and fading away toward the simplicity and insignificance of larvæ or embryonic forms? No; these most ancient Silures reject the imputation as promptly and as indignantly as any witnesses we have yet met and interrogated. On surveying these fossils, we are, it is true, forcibly and at once struck with the great change which has taken place in the inhabitants of the earth, as compared with what we found in the period of the Mountain Limestone -the change, indeed, is almost total-the population is another. But nowhere, among them all, do we detect any indication of decline or degradation in structure; nowhere do we discover such an humble exhibition of animal forms as the Development Theory would lead us to expect.

"At this ancient epoch," says St. George Mivart, "not only were the vertebrate, molluscous, and orthropod types distinctly and clearly differentiated, but highly-developed forms had been produced in each of these sub-kingdoms. Thus, in the Vertebrata there were fishes not belonging to the lowest but to the very highest groups which are known to have ever been developed, namely, the Elasmobranchs (the highlyorganized sharks and rays), and the Ganoids, a group

* See Genesis of Species, p. 156.

for which the sturgeon may stand as a type. Among the molluscous animals we have members of the very highest known class; and among articulated animals we find Trilobites and Eurypterida, which do not belong to any incipient worm-like group, but are distinctly differentiated Crustacea of no low form. We have in all these animal types nervous systems differentiated on distinctly different patterns, fully formed organs of circulation, digestion, excretion and generation, complexly-constructed eyes and other sense organs; in short, all the most elaborate and complete animal structures built up, and not only once, for in the fishes and mollusca we have the coincidence of the independently-developed organs of sense, attaining a nearly similar complexity in two quite distinct forms."*

"While it may be said in a general sense, that lower forms have preceded higher ones," said Agassiz in a recent lecture, "it is not true that all the earlier animals were simpler than the latter. On the contrary, many of the lower animals were introduced under more highly organized forms than they have ever shown since, and have dwindled afterward. Animals that should be ancestors, if simplicity of structure is to characterize the first born, are known to be of later origin; the more complicated forms have frequently appeared first, and the simpler ones later, and this in hundreds of instances. The Development assertion does not bear serious examination. It is just one of those fancied results following

* Genesis of Species, pp. 154-156.

the disclosure or presentation of a great law which captivates the mind, and leads it to take that which it wishes to be true for TRUTH."*

"It is worthy of remark," says Hugh Miller, "that the Brachiopods of the Silurian periods, in which the group occupied such large space in creation, consisted of greatly larger and more important animals than any which it contains in the present day."†

Crustaceans of very curious and complicated forms, and in no respect resembling the Trilobites, have been discovered in the Silurian Rocks both of England and America-the Pterygotus and the Eurypterus-both supposed to have been inhabitants of fresh water; quarry-men, where they were first found, from the winged form and feather-like ornament of their thoracic appendages, fancifully named them "Seraphim."

But we need not multiply illustrations: a single instance will sufficiently indicate the high animal organisms that existed in this primeval epoch-we refer to the Trilobite. During the middle and later periods of this era, trilobites abounded over every portion of the earth's surface; whole beds of rock were formed almost exclusively of their remains. The fossils of no less than four hundred different species have been discovered. And geologists know no more unique family of animals than that of the trilobites, or a family more unlike any which now exists. "In their nicely-jointed shells, the armorer of the middle ages might have found almost all

* Lect. XII., before Museum of Comparative Zoology, Cambridge. ↑ Foot Prints of the Creator, p. 209.

the contrivances of his craft anticipated, with not a few besides which he had failed to discover." They varied in size from an inch or two to a foot or more in length. The head presented, in general, the form of an oval buckler, and the body was composed of a series of articulations or rings overlapping one another, so that many of them could roll themselves up into a ball like a hedgehog. Barrande, in his interesting work on The

A. Trilobite. B. Left eye of a Trilobite magnified. C. A few facets of the eye more highly magnified.

Silurian System of Bohemia, has traced them through the various stages of their embryonic development, and shown that they underwent metamorphoses to some extent similar to certain insects. Their usual mode of swimming was upon their backs, and the places they chose for their abodes were far from shore, but commonly in shallow water. But the points in these creatures upon which we desire to fix special attention