The most remarkable part of this volume, however, is that relating to the fossil fish of the Devonian Age. This period, as is well known, has long been called the "Reign of Fishes," from the great variety of singular and grotesque forms of fish-life which then appeared and peopled the ancient seas. The greatest share in bringing to light this extraordinary series of by-gone types was borne by Hugh Miller, whose discoveries in the "Old Red Sandstone" of Scotland have won for him imperishable fame in the annals of science. The continuation, on this continent, of Miller's discoveries abroad, is here given to the world; and it is no less remarkable, perhaps indeed more so, than were his. The series of fish here described forms an extraordinary addition to our knowledge of the life of the past. The Devonian waters that spread over what is now the greater part of Ohio were inhabited by a strange race of literal sea-monsters, singular in form and gigantic in size, plated and mail-clad, and bearing all manner of elaborate weapons for offense and defense. Among them we may refer to the tribe of Chimæroids, allied to the sharks, now represented only by a few rare species, and which, though well known to have existed in later formations, has never before been discovered in palæozoic rocks. Dr. Newberry has described the new genus Rhynchodus, with several species belonging to this group. Still more singular, however, are several genera of ganoid fish, of which only one or two can be referred to here. One of these is Onychodus, which carried at the extremity of its lower jaws, where the two rami meet, a vertical set of long, radiating teeth, projecting like the piercing prow of an iron-clad ram. This form is wholly novel. Another is Deinichthys, the giant of the period, whose tremendous jaws, shaped like sled-runners, were a couple of feet in length; while the bony buckler that covered the back was from one to two inches in thickness!
But time would fail us to dwell on these interesting accounts; and we can only express our gratification that so much important discovery is now announced and recorded in a permanent form, and congratulate both the gentlemen of the survey and the people and government of Ohio on this great work now so auspiciously approaching its close.
This is said to be the book of the season, and it is creditable to the season that it is so, for it is a volume of deep and varied interest, as well as of important instruction. Without any dramatic incident or external adventure, the earnest attention of the reader is sustained by a delineation of the quiet career of a man of thought. After all, there is nothing that so concerns us, with regard to a great man, as how his greatness was reached. Mr. Mill has conducted no campaigns, explored no new countries, guided no political administrations, but through his writings he has influenced the thought of his age, in directions where thought issues in action, and his influence may thus have been deeper than if he had wielded the more obtrusive and conspicuous agencies by which men are affected. Obviously, in writing his own life, Mr. Mill did not feel that he had any greatness to take care of, and so he gives a faithful account of his development, taking the reader completely into his confidence, relating his experiences, and offering his opinions and self-criticisms with a candor and unreserve that are quite remarkable. Those who have become interested in Mr. Mill's ideas, and through them in the man, will devour the book with eager curiosity; and those who have not, can hardly fail to be incited by its perusal to the study of his works. We by no means agree with all that Mr. Mill has promulgated, and have given, in another place, the reasons for dissenting from some of his doctrines; but, while holding him as not above criticism, and as having fallen into educational error from the very greatness of his attainments, we do not hesitate to acknowledge our indebtedness to him as a great leader of liberal thought in the present age. His autobiography is valuable as a record of his own mental unfolding; but, beyond this, it has great value as a history of the rise and progress of liberalized opinion in England within the last thirty years, in the promotion of which Mr. Mill had so eminent a