ILLUSTRATIONS IN THE TEXT 



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Diagram to show the measure of the earth's surface irregularities . 11 



Map to show the reciprocal relation of areas of land and sea . . 11 



The tetrahedral form toward which the earth is tending ... 12 

 A truncated tetrahedron to show the reciprocal relation of projection 



and depression upon the surface ....... 13 



Approximations to earlier and present figures of the earth ... 15 

 Diagrams for comparison of coasts upon an upright and upon an in- 

 verted tetrahedron 17 



The continents, including submerged portions ..... 18 



Diagram to indicate the altitude of different parts of the lithosphere 



surface ............ 18 



Diagram to show how the terrestrial rocks grade into the meteorites . 22 



Comparison of a crystalline with an amorphous substance ... 24 



" Light figure " seen upon etched surface of calcite .... 25 



Battered sand grains which have developed crystal faces ... 26 



Unassimilated grains of quartz within a garnet crystal ... 28 



New minerals developed about the core of an augite crystal . . 28 

 A common rim of new mineral developed by reaction where earlier 



minerals come into contact . . . . . . . .28 



Laminated structure of a sedimentary rock 30 



Characteristic textures of igneous rocks 33 



Diagram to show the order of sediments laid down during a trans- 

 gression of the sea . .. 37 



Fractures produced by compression of a block of molder's wax . . 41 



Apparatus to illustrate the folding of strata 41 



Diagrams of fold types . . . , . V . . . . .42 



Diagrams to illustrate crustal shortening . . . . . .42 



Anticlinal and synclinal folds . . .... 



Diagrams to illustrate the shapes of rock folds ... 

 Secondary and tertiary flexures superimposed upon the primary ones 

 A bent stratum to illustrate tension and compression upon opposite 



sides 



A geological section with truncated arches restored 



Diagram to illustrate the nature of strike and dip . 



Diagram to show the use of T symbols for strike and dip observation 



Diagram to show how the thickness of a formation is determined 



A plunging anticline ......... 



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