The Fossil Plants Of The Devonian And Upper Silurian Formations Of Canada Scholars Choice Edition

Author : Sir, John William Dawson
Publisher : Theclassics.Us
ISBN 13 : 9781230400082
Total Pages : 40 pages
Book Rating : 4.4/5 ( download)

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Download or read book The Fossil Plants of the Devonian and Upper Silurian Formations of Canada written by Sir, John William Dawson and published by Theclassics.Us. This book was released on 2013-09 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1871 edition. Excerpt: ...thick, striated, broadly winged, pinna? alternate, very oblique, acute at apex, often an inch wide and six inches long, margin undulate; midrib disappearing before reaching apex, veins numerous, very oblique, curved, forking thrice very obliquely." This is one of the finest of the Devonian ferns, its pinnules being sometimes six inches in length, and at first sight reminding an observer of the Glossopterids of later rocks, though very different in their venation. The fragments in Prof. Hartt's collection appear to indicate that the fronds consisted of large oblong pinnules closely aggregated together, or attached at a very acute angle to a rachis itself broadly winged. The veins spring from a broad flat midrib at a very acute angle, and curve outward to the margin, which they meet almost at right angles. It may admit of doubt whether this fern is really a Neuropteris; but its scattered pinnules would at once by their form and venation be referred to that genus, though the habit of growth seems to have been different; and for this reason I have suggested the sub-generic name above. In the species of Neuropteris the Devonian Flora approaches very nearly to that of the Carboniferous, several of the species being closely allied to common Coal formation ferns. They are, however, distinct specifically, and on the whole of a more delicate and less massive type. The principal exception to this is the remarkable species N. Dawsoni. This, however, manifestly presents in its venation a tendency toward Cyclopteris, though the form of the leaf is so different, and it is quite likely that when more fully known it will become the type of a new genus. Genus Callipteris.--Brong. 75. Callipteris Pilosa, S.N.--(PI. XVI, Fig. 189.) Bipinnate or...