The Geological History of PlantsD. Appleton & Company, 1892 - 294 pagini |
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Pagina 9
... regarded as exceptional or rare , but is widely dis- tributed and of large amount . In Canada more especially the deposits are very considerable . The graphite of the Laurentian of Canada occurs both in beds and in veins , and in such a ...
... regarded as exceptional or rare , but is widely dis- tributed and of large amount . In Canada more especially the deposits are very considerable . The graphite of the Laurentian of Canada occurs both in beds and in veins , and in such a ...
Pagina 13
... regarded by Logan and Hunt as an altered bitumen . These palæozoic analo- gies would lead us to infer that the larger part of the Laurentian graphite falls under the second class of de- posits above mentioned , and that , if of ...
... regarded by Logan and Hunt as an altered bitumen . These palæozoic analo- gies would lead us to infer that the larger part of the Laurentian graphite falls under the second class of de- posits above mentioned , and that , if of ...
Pagina 14
... regarded as natural injections , sometimes of much beauty . In correspondence with this , while in some Laurentian graphitic rocks , as , for instance , in the compact graphite of Clarendon , the carbon presents a curdled appearance due ...
... regarded as natural injections , sometimes of much beauty . In correspondence with this , while in some Laurentian graphitic rocks , as , for instance , in the compact graphite of Clarendon , the carbon presents a curdled appearance due ...
Pagina 25
... regarded as mere spores . They should perhaps constitute a separate class or order to which the name Nematodendreæ may be given , and of which Nematophyton will constitute one genus and Aporoxylon of Unger another . * Another question ...
... regarded as mere spores . They should perhaps constitute a separate class or order to which the name Nematodendreæ may be given , and of which Nematophyton will constitute one genus and Aporoxylon of Unger another . * Another question ...
Pagina 26
... regarded as conjectural . We seem , how- ever , to have here a type of tree very dissimilar to any even of the later Palæozoic age , which existed through- out the Silurian , and probably further back , which ceased to exist early in ...
... regarded as conjectural . We seem , how- ever , to have here a type of tree very dissimilar to any even of the later Palæozoic age , which existed through- out the Silurian , and probably further back , which ceased to exist early in ...
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Termeni și expresii frecvente
abundant Acrogens aërial roots Algæ allied America animal appear arctic areoles bark beds belong bituminous branches Brongniart Calamites Canada carbon Carboniferous Caulopteris cellular character clay climate coal coal-formation conifers Cordaites cycads Dadoxylon Dawson deposits described Devonian diameter dicotyledonous Eocene Europe exogenous fact ferns flora formation forms fossil fossil plants fronds fructification fruit Gaspé genera genus Geological Society graphite Greenland gymnospermous Heer hemisphere Journal known land land-plants Laramie Laurentian leaf-bases leaf-scars leaves Lepidodendron Lepidophloios Lesquereux limestone Lower Carboniferous Lycopods macrospores matter medullary rays Mesozoic Miocene modern Nematophyton northern Nova Scotia occur outer Palæozoic period Permian pines pinnules pith present preserved probably Prof Psilophyton referred remarkable resemble Rhizocarps rocks sandstones scalariform scars Sequoia shales Sigillaria Silurian similar species specimens Sphenophyllum Sporangites spore-cases spores sporocarps stems Sternbergia structure surface Tertiary thick tion tissue tree-ferns trees trunks types Upper Cretaceous vascular vegetable wood woody