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 GEOLOGY ice, and that the Macclesfield shells and sands and gravels were pushed up from the Irish Sea by the glacier which filled it. Foreign erratics have been found by the writer at considerable heights above sea level in various parts of the Mountain Limestone district, the highest one at 1,370 feet. Miss Dale records the finding of foreign erratics in the neighbourhood of Buxton, one at the height of 1,360 feet above sea level, and considers that the ice advanced over the Col at Dove Holes, filled the valley of Buxton and flowed through the valleys of the Wye and the Dove, and the Derwent below its junction with the Wye into the Trent valley. A considerable amount of detailed work will have to be done before our knowledge of the high level drifts of the county is complete. It will probably be found that the glaciation of the uplands was much more extensive than has been supposed. Sufficient evidence has been already published to modify the theory which was formulated by the officers of the Geological Survey some years ago and founded on the evidence which had at that time been obtained. APPENDIX Want of space prevents any attempt at a bibliography of the geology of the county. Further details of some of the subjects which have been briefly dealt with in the preceding pages will be found in the following memoirs and papers : Geol. Survey Memoir North Derbyshire. This contains a bibliography to the year 1887. STOKES, A. H. ' Lead and Lead Mining in Derbyshire,' Trans. Chesterfield and Derbyshire Inst. Eng. (1880), viii. 60 et seq^. TEALL, J. J. H. British Petrography, pp. 209, 210 and plate ix. ; Igneous Rocks (1888). ARNOLD-BEMROSE, H. ' On the Microscopical Structure of the Carboniferous Dolerites and Tuffs of Derbyshire,' Quart. Journ. Geol. Soc. (1894), 1. 603-44 (i plate). ' On a Quartz Rock in the Carboniferous Limetones of Derbyshire,' Quart. Journ. Geol. Soc. (1898), liv. 169-82. 'Geology of the Ashbourne and Buxton Branch of the London and North- Western Railway (Ashbourne to Crakelow),' Quart. Journ. Geol. Soc. (1899), Iv. 224-36 (2 plates). ' On a Sill and Faulted Inlier in Tideswell Dale,' Quart. Journ. Geol. Soc. (1899), pp. 23949 (2 plates and sections). ' A Sketch of the Geology of the Lower Carboniferous Rocks of Derbyshire, 1 Proc. Geol. Assoc. (August, 1899), xvi. 165-221, pt. 4 (2 plates and sections). This sketch contains a brief bibliography of some recent papers on the Mountain Limestone. GEIKIE, SIR ARCHIBALD. Ancient Volcanoes of Great Britain (1897), ii. 8-22. 33