Mineralization at Coch, Glamorgan (Mid Glamorgan), Wales: the second occurrence of pyrobelonite

reported. It was found with other manganese and iron minerals at the site of an abandoned r9th-century manganese mine at T27 Coch near South Cornelly, Mid Glamorgan, Wales. Reflectance values for pyrobelonite from T ~ Coch, topotype material from LAngban, and for two of the minerals associated with pyrobelonite at T9 Coch, vanadinite and hausmannite, are given. Electron-probe analyses of pyrobelonite from both localities give results that are in good agreement with its theoretical composition but disagree with the only previous published analysis. THE T ~ Coch pyrobelonite was found during the course of a reflected light study of the man-ganese and iron ores collected from some small spoil tips at the site of an abandoned and infilled 19th-century manganese mine. A more complete description of the mineralogy of these ore minerals, and of the deposit, is given in Criddle (in press). Watson (1859) provided the only geological record of the deposit: it consisted of an interbedded sequence (sandwich) of 3 ft of 'hematite ' (basal), 4 ft of manganese ore, and I ft of 'hematite ' resting conformably on Carboniferous Limestone and overlain by 6 ft of Keuper conglomerate, all dipping to the south against he prevailing northerly dip of the Limestone. The lateral extent of the deposit was not recorded. From the small size of the spoil tips, from Vivian's (I884, p. 17o) commen