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 } r ears, 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 plateau wall to the north, and being 

 tilled by sediments brought by the Yellow River. 



The fossil plants brought by Pumpelly from the coal-bearing rocks 

 were studied by Newberiy and identitied as of Mesozoic age. 



George H. Cook, who was assistant geologist of New Jersey under 



the Kitchell survey (suspended in 1856), was appointed State geologist 



with the reorganization of the same survey in 1863, and continued to 



serve in this capacity until the time of his death in 



Cook's Survey of 1 



New Jersey, 1889. His first annual report, that tor 1861, bearing- 



1863-1889. ,i,,i 



the date of 1865, was a small pamphlet of but 20 pages, 

 and contained a single-page colored geological map of the State, the 

 second of its kind to be issued, the first having been by H. D. Rogers. 



l Pumpelly. 



