Abstract
IV.—THE UNITED STATES. THE United States Geological Survey frequently assists research by publications in which definite subjects are dealt with from a comprehensive point of view. The Bibliography of North American Geology for 1906 and 1907 was issued in 1909. A bibliography of Archaean and Algonkian geology, divided up under the various States, is given in Bulletin 300 (pp. 940, 1909), in which Messrs. Van Hise and Leith review the pre-Cambrian geology of North America. As the title shows, Canada is included, and the summaries given of published work make this volume welcome in every library of scientific reference. Bulletin 364 (1909) is by Messrs. Darton and Siebenthal on the Laramie basin in south-eastern Wyoming. The name Casper formation is proposed (p. 13) for Carboniferous limestones and sandstones resting on pre-Cambrian rocks on both sides of the Laramie Range. The Laramie beds, over which much discussion has arisen, may be represented by the highest sandstones and shales of the Cretaceous Montana series, and an unconformity, now widely recognised, occurs between this series and the Cainozoic beds (pp. 35 and 43). The Laramie question, it may be observed, has been recently discussed by Mr. Whitman Cross (Proc. Washington Acad. Sci., vol. xi., 1909, p. 27), who proposes the name Shoshone Group for the beds elsewhere styled Laramie, but lying above the unconformity. The coloured geological map in the memoir, and the illustrations, show well the character of the broad valley of the Laramie, with its floor 7000 feet or more above the sea,.and gneissic hills rising some 3000 feet higher on the east and west (Fig. 1). Interesting contrasts are afforded in a great variety of strata, especially where Oligocene sands form level ground in hollows of the Archaean rocks of the Laramie range.
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C., G. Recent Work of Geological Surveys . Nature 84, 121–123 (1910). https://doi.org/10.1038/084121a0
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DOI: https://doi.org/10.1038/084121a0