. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Granite having a cuboidal and rude columnar structure, Land's End, Cornwall. united in what is termed a contused crystallization; that is to say, there is no regular arrangement of the crystals in granite, as in gneiss (see fig. 756, p. 733), except in the variety termed graphic granite, which occurs mostly in granitic veins. This variety is a compound of felspar and quartz, so arranged as to produce an imperfect laminar structure. The crystals of felspar appear to h
. Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments. Geology. Granite having a cuboidal and rude columnar structure, Land's End, Cornwall. united in what is termed a contused crystallization; that is to say, there is no regular arrangement of the crystals in granite, as in gneiss (see fig. 756, p. 733), except in the variety termed graphic granite, which occurs mostly in granitic veins. This variety is a compound of felspar and quartz, so arranged as to produce an imperfect laminar structure. The crystals of felspar appear to have been first formed, leaving between them the space now occupied by the darker-colored quartz. This mineral, when a section is made at right angles to the Fig. 735. Fig. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Lyell, Charles, Sir, 1797-1875. New York, D. Appleton and co.
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectgeology, bookyear1868
