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SEE— THE NEW THEORY OF EARTHQUAKES [November 15, 



Geology. — In the work on " Geology " by Chamberlin and Salisbury, 

 Vol. II., p. 129, we find the following curious figure and explanation 

 of the elevation of the continents : 



Fig. 3. Illustration of general deformative movement, from Chamberlin 

 and Salisbury's " Geology," Vol. II., p. 129. 



" Fig. 32 C. Diagram illustrating the supposed elements of a general 

 deformative movement. 56' represents the outline of the sphere at the ocean 

 level before deformation. The dotted line represents the corresponding sur- 

 face of the lithosphere, the ocean basin occupying the center and the conti- 

 nents the flanks. S'S' represents the outline of the sphere at the ocean level 

 after deformation, the heavy line representing the outer surface of the de- 

 formed lithosphere, and the space between ^'vS' and S'S' representing (much 

 exaggerated relatively) the vertical shrinkage which is the great feature of 

 the movement but is only made apparent through its deforming effects. 

 That part of the outer shell which is beneath the ocean is supposed to descend 

 without much compression, while the necessary folding is concentrated on the 

 borders of the continent. The central portion beneath the ocean is represented 

 as descending directly toward the center. The portions on each side preserve 

 their length by thrusting laterally and hence descend along paths represented 

 by the arrow-headed lines, of which those at the border of the ocean, a, a, 

 are the most oblique and represent the greatest thrust. On the borders of 

 the continent the crust is folded to the extent of this lateral thrust. This of 

 course only holds true when the thrust is limited to a single oceanic basin. 

 The lateral thrust is chiefly felt in the outer shell or rigid zone, RZ, which 

 embraces the heavy line and the dotted zone below. Beneath this lies the 

 shear zone, SZ, whose foliated structure is represented as not unlike that of 

 the ' drag ' belt of a fault plane. The igneous sheets, batholiths, etc., which 

 are supposed to especially affect this zone are not represented. The great 



