62 ff, 



Virginia 



coastal plain of, 108 



continental terrace off, 103, 116 



submarine canyons off coast of, 116 

 Viscosity of the substratum, 33 

 Vitreous earth-shell, 33, 46 

 Volcanic heat, origin of, 56 ff 

 Volcanic islands of sea floor, 50 



catastrophic changes of, 52 ff 



loads on the earth's crust, 60, 

 65, 67, 97 



tests of crustal strength, 60, 62 ff 



upbuilding of, 50 

 Volcanism, in relation to substratum, 57, 



97 



W arping of the geoid, 25, 27 

 Washington Canyon, 116, 119 

 Water-gages of the Great Lakes, 44 

 Wave-base, defined, 52, 69, 100 

 Waves, elastic, seismic 

 body, 15 



INDEX 177 



compressional, longitudinal, or push, 



M 



Love, 17 



Main or Long, 14 



pseudo-Rayleigh, 16, 19, 20 



Rayleigh, 16 



Surface, 15 



Surface-shear, 17 



Transverse, Shear, or Shake, 14,18,47 

 West Indian archipelago 



gravity in, 95 ff 



mountain chain of, 80, 82, 95, 98 

 Wilmington Canyon, 116, 118 

 Wilson, J. T., investigator of the sub- 

 oceanic crust, 21, 165 

 Wisconsin stage of the Glacial Period, 



I2 8 

 Woods Hole, Massachusetts, 108, no 

 Wiist, G. See Figure 1 



I oldia Sea, 39 

 Yucatan, continental terrace off, 8 







