Review: North American Fossil Crinoidea Camerata
Charles R. Keyes
The Journal of geology
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... ntent at http://about.jstor.org/participate--jstor/individuals/early-journal--content. JSTOR is a digital library of academic journals, books, and primary source objects. JSTOR helps people discover, use, and build upon a wide range of content through a powerful research and teaching platform, and preserves this content for future generations. JSTOR is part of ITHAKA, a not--for--profit organization that also includes Ithaka S+R and Portico. For more information about JSTOR, please contact firstname.lastname@example.org. REVIEWS 221 degradation. In the degradation of such a plane the material is not taken up once for all and carried out to the sea (except of course that held in suspension), but is shifted little by little through cutting here and filling there, until, piece by piece and shift by shift through almost endless repetitions, the material is at length transferred to the sea. The newly formed portions of the equated plane would be liable to suffer this process over their whole surface during the stage of equilibrium and the early stages of degradation. It would be only when the degradation of the portions down stream had increased the gradient to such an extent as to lead to a contraction of the channel and the abandonment of a portion of the flood plane, that reworking of the surface parts would cease. If, therefore, we assume the style of fluvio-glacial deposition postulated by Professor Wright, we find definite reasons for regarding the upper part of the Brilliant deposit as postglacial in origin, and find moreover special conditions that may have subjected it to reworking during the early stages of degradation that followed its construction. If, on the other hand, we assume that the glacio-fluvial deposits took the form of a common aggradation plane at the close of glacial action, the presumption is that the Brilliant terrace was carved out much later. It is just possible that the Brilliant deposits happened to be at the pivotal point between degradation and filling, and so were originaland the review admitted that they might be-but the more the case is studied the less probable this seems. T. C. C. North American Fossil Crinoidea Camerata. By CHARLES WACHS -MUTH and FRANK SPRINGER. (Memoirs Museum of Comparative Zoölogy.) Two parts, 800 pages, and atlas of 83 plates. Cambridge, 1895. During the decade just passed our knowledge of ancient organisms has been enormously expanded, not so much through the old grooves of endless multiplication of species, as along lines in which the most recent conceptions of morphological inquiry are taken into consideration; or along lines having a direct bearing upon the interpretation of geological phenomena. Hence the differentiation of modern palaeontology has been chiefly in two directions, and these departments are becoming so widely divergent that they will ere long, if some energetic steps are not taken to prevent it, cease to be of mutual aid. The 222 REVIEWS science as originally inaugurated was the foundation of modern stratigraphical geology; but of recent years the biological interest has developed so rapidly with the vast accumulations of remains of ancient organic life that this branch of the subject bids fair to soon cut loose entirely from the parent stem. No better illustration of this tendency has been shown than at a late gathering of the principal scientific societies of America. Of all the palaeontological papers presented at the meetings not a single one was read before the Geological Society; the entire list was discussed at the biological associations. The impetus given to palaeontology in the direction of pure biology is timely, and the delay in entering that field may be ascribed chiefly to lack of sufficient and proper material for satisfactory study. The palae- ontologists of the new school have taken up the discussion of live organisms and their examination according to the latest and most approved methods in order that the long extinct forms of life might be interpreted more correctly. And the most advanced students of existing beings are beginning to look with less aversion than formerly to the fossils for the missing links for a complete phylogeny and ontogeny of living things. As the result of it all the value of organic remains for solving the intricate problems of the stratigraphic geology will be increased a hundredfold. The exhilarating effects have already begun to be felt in that branch of geological inquiry that was thought to be all but inert. The life and racial histories of fossil vertebrates have for some time past yielded most beautiful and suggestive results. In the same direction the vastly more extensive groups of the invertebrate has in this country at least received scarcely a thought. Palaeontologists therefore will hail with delight the appearance of Wachsmuth and Springer's masterly and exhaustive monograph on the North American camerata the most important branch of the crinoids. While it is first of all morphological from the foundation up, and the product of inquiries more thoroughly grounded in biological philosophy than any other work perhaps that has ever been issued on the fossil invertebrates in this country, it is also of such high utility in stratigraphy, especially in the great Mississippi basin, that it may be truly said no other one work has ever furnished so valuable criteria for the purposes of correct correlation of geological formations. Of all fossil remains none are more admirably adapted for morphological study than those of the echinoderms. On account of their REVIEWS 223 abundance, their peculiarities in geographic and geologic distribution, and their structure, the stalked feather stars or stone-lilies are preeminent. With the skeletal parts composed of regular plates or ossicles, definitely grouped and frequently highly sculptured, all structural changes are readily deciphered. The work on the crinoids is the outgrowth of studies begun more than twenty years ago, under the encouragement of Louis Agassiz, and prosecuted without intermission ever since. The entire work as contemplated will form two huge quarto volumes, of which the first, in two parts with an atlas of plates, has just been issued. Of the text there are nearly 800 pages; and the plates number 83, comprising 1500 illustrations artistically reproduced as photogravures. In the present installment-the Crinoidea Camerata-there are three main subdivisions; introductory, morphological and descriptive. The introduction embraces an historical résumé of opinion and a full explanation of the terminology employed in description. Special attention should be called to the clear and concise definitions given of the various structural parts. The terms should be universally adopted as they form by far the best collection ever proposed. American writers especially will need no appeal to at once use them not only to secure uniformity in nomenclature but precision of description. Heretofore the names of the various plates or groups of ossicles have been used in a rather haphazard way. Not only have different designations been given to the same part, but the same title has been repeatedly applied to structures widely separated morphologically. The morphological part contains the full discussion of the data upon which the entire classification of the crinoids rest, of the genetic relationships of the various groups, and of the structural characteristics. The plates in general are separated into "Primary" and "Supplementary" pieces. The former occur in every crinoid and comprise the ossicles represented in the early larva, the basals, the infrabasals, the various plates of the rays or arms, the orals, and the joints of the stem. The supplementary pieces, which make their appearance in the more advanced stages, but which are altogether unrepresented in some groups, comprise the remaining plates. The primary ossicles belong either to the "abactinal" or to the "actinal" system. Those of the former including all the plates, connected with the chambered organ and axial cords; the others comprising those communicating with the mouth and the annular vessels surrounding it.