Chap. 9] 



SEISMIC METHODS 



469 



Table 48 

 ALLUVIUM, DILUVIUM— GLACIAL DRIFT 



" Round figures such as these indicate values by investigator. 



* These figures are the equivalent in feet (from conversion tables). Investigators in countries using, 

 metric systems usually give velocities in m.8ec.~M those in countries using the English system, in ft. .sec."* 



Table 49 

 SANDS, CLAYS, MARLS 



