DISCOVERY BY REFLECTION SEISMOGRAPH 49 
T15n alle 


LEGEND 
50-023 depth shot hole with vertical elapsed time 
x) Shot hole 
38 thickness. soil or alluvium from drill record 
Fic. 4 
depth in the bed rock and terminated in shale. The six pickups were 
placed in a line away from the shot point at a distance of from 800 to 
1,300 feet. The pickups in this case were buried to a depth of 2 feet. 
293 
