. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. AMEEIOAN GEOLOGY DECADE OF 18(>0-18fi9. 523 plates of sections, and a colored geological map, the latter confessedly hypothetical. This memoir, which antedated Richthofen's great work on China by some }rears, gave to the world the first authentic account of the geology of the region. He showed that in the region extending from the twentieth to a little beyond the fortieth parallel and from near the one hundredth to about the one hundred
. Annual report of the Board of Regents of the Smithsonian Institution. Smithsonian Institution; Smithsonian Institution. Archives; Discoveries in science. AMEEIOAN GEOLOGY DECADE OF 18(>0-18fi9. 523 plates of sections, and a colored geological map, the latter confessedly hypothetical. This memoir, which antedated Richthofen's great work on China by some }rears, gave to the world the first authentic account of the geology of the region. He showed that in the region extending from the twentieth to a little beyond the fortieth parallel and from near the one hundredth to about the one hundred and twenty-second meridian the oldest sedimentary rocks were Devonian limestones, which prevailed in some cases to the enormous thickness of 11,600 feet. Overlying this, through the greater part of the area, were the Chinese Coal Measures (Mesozoic), interrupted by bands of granitic and metamorphic rock of undeter- mined age. In the extreme northern part of this region was a com- parative^ small area of basaltic and trachytic rocks. The region immediately south of Peking, comprised principally within the prov- inces of Chihli, Nganhwui. Kiangsu. and Shantung, was colored, as occupied by post-Tertiary materials, with smaller areas of the same age along the Yangtse-Kiang and Hoangho rivers in the provinces of Hupeh, Sz'chuen, and Shensi. Considerable attention was given to the post-Tertiary li Terrace" deposit, or loam, which he found in the valley of every tribu- tary of the Yang Ho, and probably also of the Sankang Ho. This, which has since be- come more generally known as the Chinese loess, was described in considerable detail as to modes of occurrence, physical properties, and geological distribution. The material he regarded as having been deposited in a chain of lakes extending from Yenkingchau north-northwest of Peking to near Ninghia, in Kansuh, a distance of nearly 500 miles, the lake basins themselves being formed by the dis- locations which gave rise to the platea
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