Comment and Reply on "Mesozoic overthrust tectonics in south China" COMMENT David B. Rowley, Alfred M. Ziegler, Nie Gyou, Department of Geophysical Sciences, 5734 S. Ellis Avenue, University of Chicago, Chicago, Illinois 60637 Hsu et al. (1988) presented their views as to the regional structure and tectonics of the Jiangnan-Xuefeng of south China. They presented reinterpretations of two basic aspects of the geology of this region: (1) The cross-sectional geometry of the Jiangnan-Xuefeng belt of south China consists of west-vergent folds and thrusts, including a lower assemblage of shelf-type sediments (so-called cover thrusts), structurally overlain by me- lange with ophiolitic slabs (so-called Banxi melange), in turn overthrust by "rigid basement" nappes. (2) This geometric arrangement resulted from a collision between the Yangtze and Cathaysia (southeastern south China) blocks during Mesozoic time. We believe that the interpretations of Hsu et al. (1988) obfuscate the well-known geologic relations within this region, and we present geologic maps that show some of the stratigraphic and structural relations in two regions of the Jiangnan-Xuefeng belt to demon- strate our questions concerning their interpretations. Hsu et al. (1988) reinterpreted the contact relations in the Jiangnan- Xuefeng belt of south China (outlined in Fig. la) as Mesozoic age thrusts of Banxi melange over adjacent sediments. The original Chinese maps (Fig. lb) present interpretations of most of these contacts as Sinian uncon- 384 GEOLOGY, April 1989