File:The Quarterly journal of the Geological Society of London (1859) (14578565408).jpg

Identifier: quarterlyjournl151859geol (find matches)
Title: The Quarterly journal of the Geological Society of London
Year: 1845 (1840s)
Authors: Geological Society of London
Subjects: Geology
Publisher: London (etc.)
Contributing Library: Smithsonian Libraries
Digitizing Sponsor: Biodiversity Heritage Library

View Book Page: Book Viewer
About This Book: Catalog Entry
View All Images: All Images From Book
Click here to view book online to see this illustration in context in a browseable online version of this book.

Text Appearing Before Image:
ssue is pre-served, the Museum is indebted to Mr. Wariagton Smyth (MiningGeologist to the Geological Survey). It is figured at pi. 2. fig. 1,and consists of the silicified lower portion of a rootlet, the sides ofwhich have collapsed, so as to reduce its originally cylindrical formto that of an irregularly four-sided prism. The substance is formedof a network of exceedingly delicate cellular tissue (pi. 2. figs. 2and 3), composed of hexagonal cells; and it is traversed through-out its length by a dark line (fig. 2a), no doubt indicating the pro-longation of one of those slender bundles of vascular tissue whichissue from the medullary rays of the axis (a of figs. 6 and 7), andthence proceed to the mamillae on the surface of the specimen, * Some to whom this specimen has been shown regard these tubes as beingdue to the mineralized condition of the central portion of the axis; but I cer-tainly consider them to be the representatives of the vascular tissue. Quart- Jo^jin.Geol. Soc YIXYTIVJ
Text Appearing After Image:
G-TA>st del ct iifh.aijiat. ^FWet zs\^ STIC-MAELA 1858.) BINNET STIGMARIA. 79 figured at fig. 4, or the bases of the cavities in the figures in plate 1.This very simple structure of rootlet is similar to that of severalLycopodia, and indeed of many other plants, both Monocotyle-donous and Dicotyledonous, so far as can be ascertained without afarther knowledge of the axis of the organ; of the structure ofwhich, however, there can exist no reasonable doubt, since it maybe confidently assumed to consist of a bundle of vessels, similar tothose represented at fig. 7a. The specimen of the rootlet oiStigmaria now about to be described,was found by me during the last summer on an old coal-pit hill atOver Darwen, Lancashire; it occurred in a nodule of clay-ironstone,most probably derived from the roof of one of the lower seams ofthat district. The rootlet from which my sections have been madewas from a part about half an inch from the root; it is quite cylin-drical, and was originally one-f

Note About Images