. Elements of geology : a text-book for colleges and for the general reader. Geology. JURA-TRIAS IN AMERICA. 453 the greatest perfection, viz., ripple-marks, rain-prints, sun-cracks, leaf- impressions,and tracks of animals. It is evident, therefore, that this was, throughout, a littoral or slioal-icater deposit. But it is at least 5,000 feet thick. Therefore, there must have been subsidence to that extent. Here, then, we have evidence of rapid deposit (for the mate- rials are coarse), invasion of interior heat with aqueo-igneous fusion, subsidence, formation oi fissures, and ejection of lava.
. Elements of geology : a text-book for colleges and for the general reader. Geology. JURA-TRIAS IN AMERICA. 453 the greatest perfection, viz., ripple-marks, rain-prints, sun-cracks, leaf- impressions,and tracks of animals. It is evident, therefore, that this was, throughout, a littoral or slioal-icater deposit. But it is at least 5,000 feet thick. Therefore, there must have been subsidence to that extent. Here, then, we have evidence of rapid deposit (for the mate- rials are coarse), invasion of interior heat with aqueo-igneous fusion, subsidence, formation oi fissures, and ejection of lava. These sandstones are poor in fossils, but the few that are known in- dicate the horizon of the Keuper or Upper Triassic of Europe. As these are found near the middle of the series, it is probable that the series represents the whole of the Trias and part of the Juras of Europe. The Record.—The general redness of the sandstone is sufficient evi- dence that organic remains are very scarce; and so, indeed, we find Fig. 714.—a, Frond; b, Cone (after Hitchcock). Two or three fishes, a few leaves, the most perfect of which is a species of fern—Clathopteris—and a fir-cone (Fig. 714), and a few small frag- ments of thin, hollow bones, which may have belonged to either birds or reptiles, are all that have been-yet found. But by far the most interesting portion of the record in this locality consists of tracks. These are partly tracks of Insects and Crustaceans,. 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 LeConte, Joseph, 1823-1901. New York : D. Appleton and Co.
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1892
