Page:The American Cyclopædia (1879) Volume XII.djvu/822

808 of Alexandra Brongniart on fossil Crustacea, and of Adolphe Brongniart on fossil botany, accomplished much for the advancement of palæontology, and aided greatly in giving it rank among the natural sciences. The names of Schlotheim, Wallenberg, and others are connected with the investigations of organic remains in the early part of the 19th century; and from that time progress in the science has been so rapid, and authors so multiplied, that even the names cannot be enumerated in a sketch like this. Thus it is seen that only after long continued series of observations, carried on amid prejudices which blinded the judgment, men came finally to the conclusion that fossil organic bodies are representatives of the animals which inhabited the ocean bed at successive and remote intervals; and that they occur in the rocky strata precisely as they were imbedded in the mud or sand beneath the waters, or as they lived in the littoral belt along the shore line, where they were sometimes mingled with plants or animals of terrestrial origin.—It was, as we see by the history of scientific progress, a long and tedious process to prevail upon the human mind to dismiss the notion of the sudden creation of the earth and its inhabitants, and to recognize the creative energy extending through myriads of ages; to admit the fact that the dry land on which we stand was simply formed by the successive depositions of mud, sand, and gravel made upon the bottom or borders of the ocean, and that these were marked by the remains of those animals which lived at the time, as similar forms now live, in the oceanic waters; and finally, that these layers of rock, of whatever kind, mark certain eras, and contain an indelible record, more or less complete, of the conditions then existing, and of the changes which have brought about the later and present state of things. After much study and patient investigation the conclusion has been reached that, with very small exceptions, the dry land has resulted from the gradual uplifting of the ocean bed, carrying with it organic and inorganic material, in undisturbed or partially disturbed condition. An investigation of these materials, constituting the earth's crust, proves that organic life has been as effective in the earth's past as in its present conditions. It is the history, influence, and relations of this ancient organic world which constitute the science of palæontology in all its departments, and when fully understood will give us a better knowledge of the early conditions of the surface, the gradual progress through various phases, and the clear unbroken line from the earliest organisms to the advent of man upon our planet. The beginning, rise, and progress of the science of palæontology have been coincident with those of geology, since the latter was separated from the speculations of cosmogony, and became a science of observation and of legitimate induction. As geology was long regarded as a subordinate de- partment of mineralogy, and sometimes of physical geography, so also it is only by slow steps that palæontology has assumed sufficient importance to be considered apart from its kindred science. The one characteristic feature in the rapid progress of geology during the present century has been the growing recognition of the importance of organic remains, and the increased attention and study given to this department of natural history. In all investigations among the stratified unmetamorphic rocks, this subject is of paramount importance; and even among the metamorphic rocks the aid of palæontology is sometimes of great advantage in our determinations. Zoölogy and botany have also partaken of this influence. Constant discoveries have created new demands upon the knowledge and acumen of the comparative zoölogist and botanist. The imperfect, fragmentary, or obscure condition of fossil remains has demanded the closest scrutiny of their external parts and of their most intimate structure; and it is to the reaction of this study of fossil organisms upon the methods of study in the living fauna and flora that we are indebted for a better knowledge of structure, and the filling up of gaps in our series; thus giving a truer arrangement and classification of existing forms by intercalating the fossil organisms in their proper relations.—The term "fossil" may be defined, according to M. Deshayes, as follows: "An organized fossil body is one which has been imbedded in the earth at an unknown epoch, which has been there preserved, or which has left there unequivocal traces of its existence." This excludes from the term the modern remains of plants and animals which have been buried and lost by the floods, land slides, or accidental causes of our times. This definition being adopted, it is easy to fix the limits of palæontology. In the present action of natural causes, we see analogies for the history of fossils imbedded in the strata of the globe. Streams, floods, and the action of waves bear along gravel, sand, or silt, and deposit them in quiet waters, the heavier materials first and underneath, the lighter above and more widely diffused, forming superimposed beds, all differing more or less in com- position. A long continuation of this action may produce beds of great thickness, parallel in stratification, and in the course of their slow formation shells may gather and plants may grow, and gradually become buried by the new accession of drifting material. The first condition of these deposits is horizontality; subsequent disturbing forces may lift, or break, or disarrange them, and the gradual rising or sinking of certain portions of coast line or ocean bottom, as now taking place, must eventually produce such effects as here indicated. The study of the rocky strata shows that the same conditions, the same characters, the same accidents as these prevailed during their formation; and far from the necessity of supposing violent cataclysmic force, it is only necessary