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Figure 11. Type 47 Polaroid Film Record. The sharp breaks are typical 

 o£ good energy transmission through water-soaked sediments. 

 The vertical lines are spaced 10 milliseconds apart. The 

 13 traces include one shot break and 12 geophone channels. 

 Arrivals can be picked to the nearest millisecond. With 

 the exception of the "-4" at the left of the caret, the 

 handwritten numbers are the arrival times in milliseconds. 

 The "-4" is a constant indicating the shot break's relation- 

 ship to the initial timing line marked by the caret. Arri- 

 vals are timed from the initial time line and the constant 

 is then substracted from raw times to give real times 

 written on the record. The almost simultaneous arrival 

 of the last five phones probably indicates rising bedrock. 



17 



