Download or read book American fossil cycads 2 Taxonomy written by George R. Wieland and published by . This book was released on 1916 with total page 277 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads Vol 2 written by G. R. Wieland and published by Forgotten Books. This book was released on 2018-03-11 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from American Fossil Cycads, Vol. 2: Taxonomy When the hard - won results of the students of other days, the tedious processes of earlier book-making, and especially the difficulties involved in securing adequate illustra tion are considered, the writer esteems himself peculiarly fortunate in having had the aid and advice of the Officials of the Carnegie Institution of Washington in bringing tlu's supple mentary volume to successful publication. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Download or read book American fossil cycads 2 Taxonomy written by and published by . This book was released on 1916 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads Vol 2 written by G. R. Wieland and published by Forgotten Books. This book was released on 2015-06-02 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from American Fossil Cycads, Vol. 2: Taxonomy In brinsring to completion a second volume on the petrified cycads the material inviting exact study seems more impressive than ever. The actual number of stems in the several collections has not been much increased since the publication of Volume I, but the aggregate of finely conserved structure which is gradually being located and made available for study is great. Nordo the European collections fall behind those of America in interest. Although somewhat less extensive, their structural interest coequals that of the American collections. Easily the most noteworthy addition to the American series is the monocarpic trunk of the United States National Museum discovered by Dr. N. H. Darton in the Hermosa segment of the Black Hills Rim in certain respects the most remarkable fossil plant of any kind or age ever recovered. Fortunately, however, the study of the Cycadeoids has reached a point where progress is less dependent on rare or unusually conserved specimens. To this result the discovery of related Williamsonians has greatly contributed; equally so the precise methods for the study of casts and imprints introduced by Professor Nathorst and others. The expanding field of cycad investigation has thus taken on permanent interest, and it is certain that museum collections will be signally enlarged, while those already accumulated hold the attention of botanists. In the prefatory note to Volume I the opportunity for extended study and comparison of Cycadeoidean seeds was emphasized, and it is believed that the chapter now devoted to this subject fully justifies singling it out. Even without the increase of material afforded by the Hermosa cycadeoid it was evident that the seeds held far greater interest than the space earlier devoted to them indicated. At the present time, amongst subjects near at hand, the simpler one of stem structure may be noted. The anatomy of the fossil gymnosperms has long been an unsatisfactory subject because of the great size or fragmentary character of the Mesozoic stems. The wedge of a Cycadcoidca trunk is comparable to the wedge of even the tallest conifer. It affords complete structural details within restricted limits and later studies will reveal the type of change which may be expected in gymnospermous stems in passing from pith to cortex and from base to apex. The unexpected discovery of the homed disks of Cycadeoidea colossalis has led to comparisons with seed-coats suggesting some kind of ancient and far-reaching homology between megaspore and floral envelopes. The ideas advanced are not theories; they are hypothetic. If any of these conceptions should later receive confirmation or proof their importance in evolutionary theory must be very great. For this reason the discussions of the closing chapters take on a speculative form. No claim of triumphant demonstration is made or under the circumstances can be made. Refutation there may well be. But in either instance it is with confidence that the group origins are held to be more nearly discrete than may be implied from most discussions of the theory of descent. It has been found necessary to lay increasing stress on the need for adhering to the nomenclature of convenience already established for the silicified stems. This is indispensable to progress in the taxonomy, and to a certain extent in general structure. These stems are unique, and must be recognized as difficult to catalogue. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com
Download or read book AMERICAN FOSSIL CYCADS written by G. R. WIELAND and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads written by George Reber Wieland and published by . This book was released on 1916 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads written by George Reber Wieland and published by . This book was released on 1916 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads written by George R. Wieland and published by . This book was released on 1916 with total page 335 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads written by G. R. Wieland and published by Forgotten Books. This book was released on 2015-06-02 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from American Fossil Cycads The investigations here recorded were begun in the field in 1898. During the summer of that year, while collecting Testudinata in the "Bad Lands" of the Cheyenne River and Dinosauria in the nearby Rim of the Eastern Black Hills, I had many opportunities for visiting and carefully examining the famous Black Hawk cycad locality, to which my attention had been previously directed by Professor Marsh, when the season's work was planned. It was, too, during the fall of 1898 that, as is more fully related in the fourth chapter, I had the good fortune to discover, well to the north of the old Black Hawk locality and to the east of Piedmont, the fossil cycad bearing the most perfectly silicified prefoliate fronds of any yet obtained. Soon after this discovery, furthermore, Professor Lester F. Ward, whom I then met for the first time, revisited the Piedmont-Black Hawk region. Thus I found myself in touch with the two men of all others in this country most interested in the fossil cycads - the one primarily in securing a great and representative collection, the other in making these peculiarly interesting and problematic forms accessible to the further study so urgently required; and I returned to New Haven with the fixed intention of attempting a complete elaboration of the structure of the Mesozoic cycads as soon as might prove feasible. The necessity for the proposed series of thin sections was fully appreciated by Professor Marsh, and it was particularly pleasing to me that he was able to take part in the discovery of the staminate disk and foliage which was made shortly thereafter. The subsequent course of these studies is of lesser moment in this connection. As I have made all of the sections and most of the photographs and photomicrographs, it is evident that the labor involved has been arduous, however replete with interest. With respect to the mode of presentation of relationships in the two closing chapters, it may be said that the form adopted appeared the most practical in the present status of laboratory study of the existing cycads, and field and laboratory study of the fossil cycads. I am keenly aware that the conclusions reached therein can be at the best but tentative ones, and that, above all, the paleontologic record must be laboriously scanned afield for many years before mere hypothesis can be thrust aside for the clear and established truth. But it can not be doubted that it is fully possible to accomplish a final and satisfactory solution of the still largely obscure and hidden phases of homoplasy and parallelism involved in the origin of cycadaceous plants, the fuller knowledge of which is so centrally fundamental to an empiric conception of gymnosperm and perhaps even angiosperin evolution. In taking up the study of the cycads at the point of relative urgency, and following the initial macroscopic descriptions by Ward, it has not been thought either necessary, or in any sense a convenient method, to attempt to deal, in this volume, with any of the minor questions of classification and nomenclature. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Download or read book A Catalogue of the Mesozoic and Cenozoic Plants of North America written by Frank Hall Knowlton and published by . This book was released on 1919 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads Volume 2 Primary Source Edition written by Anonymous and published by Nabu Press. This book was released on 2014-01 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a reproduction of a book published before 1923. This book may have occasional imperfections such as missing or blurred pages, poor pictures, errant marks, etc. that were either part of the original artifact, or were introduced by the scanning process. We believe this work is culturally important, and despite the imperfections, have elected to bring it back into print as part of our continuing commitment to the preservation of printed works worldwide. We appreciate your understanding of the imperfections in the preservation process, and hope you enjoy this valuable book. ++++ The below data was compiled from various identification fields in the bibliographic record of this title. This data is provided as an additional tool in helping to ensure edition identification: ++++ American Fossil Cycads, Volume 2; Issue 34 Of Carnegie Institution Of Washington Publication; American Fossil Cycads; George Reber Wieland Carnegie Institution of Washington, 1916 Science; Life Sciences; Botany; Cycadaceae, Fossil; Cycads, Fossil; Science / Life Sciences / Botany; Science / Paleontology
Download or read book Fossil Plants written by Albert Charles Seward and published by . This book was released on 1919 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads written by Anonymous and published by Franklin Classics. This book was released on 2018-10-15 with total page 398 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important and is part of the knowledge base of civilization as we know it. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. To ensure a quality reading experience, this work has been proofread and republished using a format that seamlessly blends the original graphical elements with text in an easy-to-read typeface. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book American Fossil Cycads written by George Reber Wieland and published by Andesite Press. This book was released on 2015-08-09 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book Supplement to Catalogue of Mesozoic and Cenozoic Plants of North America 1919 37 written by Robert Smith LaMotte and published by . This book was released on 1944 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book American Fossil Cycads Issue 34 written by George Reber Wieland and published by Palala Press. This book was released on 2018-02-22 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work. This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
Download or read book Monthly Bulletin written by St. Louis Public Library and published by . This book was released on 1918 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Teachers' bulletin", vol. 4- issued as part of v. 23, no. 9-
