be 
In addition the data from the floating stations can be correlated with the 
seismic studies which give the dip and depth of sub-bottom reflections as 
well. On many of the echo sounder records taken at Station Charlie, an 
arrival immediately after the first bottom echo is noted. This is probably 
a reflection from a sub-bottom layer. However, the outgoing ping was not 
recorded on the fathogram and there is a small possibility that it is a 
product of the outgoing ping wave shape. Future depth sounder models will 
incorporate a circuit to record the outgoing ping directly on the fathogram. 
Seismic refraction studies were made at Station Alpha during 1958 
and at T-3 during 1960. The travases at Alpha were made on foot with the 
equipment pulled on sled. In the summer a rubber one-man rubber life raft 
was tied on the sled and was used for crossing leads. The inflated raft was 
towed until a lead was reached, then the raft was launched for crossing the 
lead. The sled was not detached. Communications proved to be the biggest 
difficulty. Efficient radios on a frequency low enough to be dependable 
were not available. In the spring a back-pack of a spool of line wire was 
used to lay a telephone line. This worked on one occasion out to five miles. 
The wire was inexpensive enough to abandon after use. However, it was 
delicate and difficult to handle. For the successful shots the time 
difference between the air-wave and water-wave arrival was used for timing. 
This method involves some error and is useful for short distance but could 
not be continued to large distance due to the attenuation and uncertain 
velocity of the air wave. The refracted wave from beneath the crust was 
not obtained as a first arrival. The highest velocity found was 6.4 km/sec. 
at a depth of 5 km. The layeving resembles an oceanic section but more 
study is needed to definitely delineate Arctic Ocean structure. The refraction 
arrivals were recorded on geophones and the various arrivals are clearly seen 
on the oscillograph record. Another advantage in recording in this area is 
the low noise level. The usual ship noises and water noise encountered at sea 
