xiv. THE ELEMENTS OF ECONOMIC GEOLOGY

FIG,
4I. The Bilbao anticline . .
42. Lake Superior iron ores 3 3 z
13. Lake Superior ores bounded by an impermeable surface
"4. ton ore at Gellivaara . . . 3 .
. Magnetite of the Adirondacks replacing felspar and quartz
<u. The ore-sheet of Kirunavaara
47. Various processes of bauxite formation.
8. Formation of mica in gneiss .
49. Chlogopite lode at Loughborough .
50. China-clay mass in Cornwall - »
51. China-clay passing into quartz-porphyry
52. China-clay produced by acids from brown coal
53. Phosphate formation . . . .
54. Section across the German potash fields showing the relations of
the four types of occurrence . . .
55. Salt dome at Baicoi oilfield . . . '
56. Section across the German potash field north of the Harz Moun.
tains . . * 6
57. The water table in an island . .
58. Underground water level and piezometers
59. Circulation of water in a porous bed '
60. The ascent of water by rock pressure, Kynuna
61. Changes in the East Anglian estuaries ;
62. Shoaling of the Ceara breakwater, Brazil
53. Comparative oilfield sections « 2

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