Acadian geology. [With] Suppl. chapter. [With] |
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Common terms and phrases
abundant Acadia Alethopteris appear Arisaig Bay of Fundy beds bituminous limestone Blomidon boulders Briar Island Brongn Brunswick Calamites Cape Breton Carbon Carboniferous rocks character clay cliff Coal measures Coal-group coaly shale coarse coast Cobequid Cobequid Mountains colour conglomerate contains Cordaites Cyclopteris Dawson Dendrerpeton deposits Devonian erect tree extending feet ferns flattened forest fossils fragments genus geological granite gray sandstones Gray shale gypsum Hartt inches iron ironstone Island Joggins layers Lepidodendron Lepidophloios Lower Carboniferous Lower Coal margin matter metamorphic mineral charcoal Naiadites nearly Nova Scotia observed occur period Pictou pinnules plants portion posterior present probably Professor red sandstone reddish resembling ridge River sand sandstones and shales seam shells shore Shubenacadie side Sigillaria Silurian slate soil species specimens Spirorbis St John Stigmaria stone striæ surface Sydney thickness tissue trap trunks underclay Upper Coal formation Upper Silurian vegetable veins Windsor
Popular passages
Page 296 - Descriptions of new species of fossils from the Palaeozoic rocks of the western states: Chicago Acad.
Page 69 - Nor would I exclude altogether the action of glaciers in eastern America, though I must dissent from any view which would assign to them the principal agency in our glacial phenomena. Under a condition of the continent in which only its higher peaks were above the water, the air would be so moist, and the temperature so low, that permanent ice may have clung about mountains in the temperate latitudes. The striation itself shows that there must have been extensive glaciers as now in the extreme Arctic...
Page 432 - Are we to infer from these facts that the wood of the trees of the genus Dadoxylon was necessarily of a lax and perishable texture. Its structure, and the occurrence of the heart wood of huge trunks of similar character in a perfectly mineralized condition. would lead to a different conclusion ; and I suspect that we should rather regard the mode of occurrence of sternbergia as a caution against the too general inference from the state of preservation of trees of the coal formation, that their tissues...
Page 429 - It also shows that the coaly coating investing such detached pith casts is not the medullary sheath, properly so called, but the outer part of the condensed pith itself. The examination of this specimen having convinced me that the structure of Sternbergiae implies something more than the transverse cracking observed in Juglandaceae, I proceeded to compare it with other piths, and especially with that of Cecropia Peltata...
Page 23 - When a shower of rain falls, the highest portion of the mud-covered flat is usually too hard to receive any impressions ; while that recently uncovered by the tide near the water's edge is too soft. Between these areas a zone occurs, almost as smooth and even as a looking-glass, on which every drop forms a cavity of circular or oval form, and, if the shower be transient, these pits retain their shape permanently, being dried by the sun, and being then too firm to...
Page 533 - Coal formation. 5. The Devonian flora was not of lower grade than that of the Coal period. On the contrary, in the little that we know of it we find more points of resemblance to the floras of the Mesozoic period, and of modern tropical and austral islands, than in that of the true Coal formation.
Page 58 - Sigillarias and other trees, of which they evidently represent flattened specimens, or rather the bark of such specimens. Under the microscope, when their structures are preserved, these layers show cortical tissues more abundantly than any others. (4.) Some thin layers of coal consist mainly of flattened layers of leaves of Cordaites or Pychnophyllum.
Page 50 - The seeds of many forest trees, especially the poplar, the birch, and the firs, and spruces, are furnished with ample means for their conveyance through the air. The cottony pappus of the poplar seems especially to adapt it for this purpose. The seeds of the wild cherry, another species of frequent occurrence in woods of the second growth, are dispersed by birds, which are fond of the fruit ; the same remark applies to some other fruit-bearing species of less frequent occurrence. When the seeds that...
Page 428 - They are rather less than one tenth of an inch apart, and are more regular than is usual in these fossils. The outer surface of the pith, except where covered by the remains of the wood, is marked by strong wrinkles, corresponding to the diaphragms. The little transverse ridges are in part coated with a smooth tissue similar to that of the diaphragms, and of nearly the same thickness. When traced around the circumference or toward the centre, the partitions sometimes...
Page 59 - ... resist the penetration of mineral substances more than other vegetable tissues. These qualities are well seen in the bark of our American white birch. It is no wonder that materials of this kind should constitute considerable portions of such vegetable accumulations as the beds of coal, and that when present in large proportion they should afford richly bituminous beds. All this agrees with the fact, apparent on examination of the common coal, that the greater number of its purest layers consist...