FOUNDATIONS OF THE GREAT DEEP 



43 



S WEDF.N 



FIGURE 21. MAP SHOWING MEAN ANOMALIES OF GRAVITY IN THREE BELTS 

 OF FINNISH TERRITORY, CONCENTRIC WITH THE CENTER OF FORMER 



GLACIATION. 



on and the negative load decreases correspondingly. When we 

 note that the shearing strength of ordinary rock is measurable 

 in many hundreds of atmospheres, and that the strength of the 

 outer half of the earth's crust is still greater, we see that the 

 subcrustal layer has comparatively little power of resistance to 

 shearing pressure. In fact, the test with the ice-cap leaves one 

 in doubt that this material has any strength whatever. 



