ILLUSTRATIONS. V 



Page 



Becker : Figure 1— Scission 24 



" " 2 — Range of circular Sections 32 



" " 3 — Stresses in finite Shear 36 



" " 4— Systems of Forces 41 



" " 5— Plastic Solid under Pressure 47 



" " 6— Strained Cubes 56 



" " 7— Widest possible Spacing of Fissures 57 



" " 8 — Spacing <>f Fissures 58 



" " 9— Effect of Potation on Fissures 59 



" " 10— Results of Rupture by Pressure at 30° to fixed Plane 63 



'< " 1 1— Results of Rupture by Pressure at 60° to fixed Plane 63 



" " 12— Contraction of Mass cooling from one Side 69 



" " 13— Primary tension Cracks 70 



" " 14— Secondary tension Cracks 70 



" " 15 — Cooling of Columns 71 



" " 16— Paul uve's Experiment on Crushing 74 



" " 17— Steps in Slate 76 



" " IS— Origin of Cleavage in Wire 80 



" " 19— Development of Cleavage by Extrusion '. 81 



" " 20— Development of Cleavage by direct Pressure 82 



" " 21— Effects of Compressibility 85 



" " 22— Deflection of Cleavage by Grit 86 



Hicks : ' ' 1— Weather Curve '35 



" " 2— Water Curve of Erosion 136 



" " 3— Combined weather Curve and water Curve 137 



" " 4— Unstable artificial Curve 138 



<< " 5— Normal relief Form in an advanced Stage of Base-level- 



mg 1,j0 



. << " 6— Typical Profile of the drainage Slopes of Mountains 138 



« " 7 — Cross-profile of bad land Divide • • • 139 



" " 8— Illustrating the Coexistence of steep Slopes with broad 



weather Curves in an early Stage of Base-leveling 140 



" " 9— Miniature Butte in the Bad Lands 142 



" 10— Cross-section of a constructive River 143 



< : " 11— Cross-section of a river Valley having no Flood-plain . .. 145 



" 12— Cross-section of a broad Valley of the Plains having no 



Flood-plain 145 



Whittle: " 1— Thin Section of Ottrelite-schist 151 



2— Thin Section of Ottrelite 152 



'< " 3 — Thin Section of water-worn Tourmaline Pebble 157 



" " 4— Thin Section of microcline Pebble 100 



" " 5— Thin Section of microcline Pebble |( >3 



Hobbs: " 1— Examples of Deformation and modified Growths of Min- 

 eral in Schists 170 



" " 2— Secondary Enlargement of Plagioclase '72 



" " 3— Garnets with secondary Enlargements 174 



" « 4— Portion of a Crown of Staurolite and Magnetite encir- 

 cling a garnet Individual L75 



