28 ILLUSTRATIONS. 



Fig. 17. Granulation of feldspar and gradation between undulatory extinction and granu- 

 lation _ _ 674 



18. Granulation of quartz in a rook in which the feldspar is but little affected 674 



19. Liquid-filled cavities extending across several quartz individuals without change of 



direction • _ 746 



20. Diagram showing possible relation of old and new grains of recrystallized rocks 752 



21. Diagrams illustrating mass deformation of a rock 769 



22. Sketch of oval irregular grains of calcite with longer diameters parallel 810 



23. Gray wacke undergoing serpentinization along cracks 882 



24. Conglomerate deposited in depression produced by erosion of basic dike through 



gneiss 923 



25. Diagrams illustrating the manner in which deformation in the zone of flowage may 



concentrate crustal shortening in the zone of fracture _ 928 



26. Ideal vertical section of the flow of water entering at a number of points on a slope 



and passing to a valley below through a homogeneous medium interrupted by two 



open vertical channels, one on the slope and one in the valley 1076 



27. Ideal section showing underground circulation in which no water anywhere ascends 



before issuing at the surface 1080 



28. Cross section of banded vein near the London shaft, Mineral Point, Colorado 1135 



29. Diagrammatic section of Enterprise mine, Colorado, and its blanket pay shoot 1208 



30. Diagram illustrating mingling of circulations of two limestones separated by a shale. 1209 



31. Ideal vertical section of flow of underground water in the Galena limestone of the 



upper Mississippi Valley 1210 



32. Ore deposit in limestone beneath impervious shale, Elkhorn mine, Montana 1214 



