40 
MUSEUM BULLETIN NO. 25. 
particles. Sifting or sorting then takes place ; the lighter particles 
are separated and continue to move forward as before, still 
in the undulatory course which the movement always follows; 
the wave action stirring up the bottom of the troughs, carries 
the fine particles to the crests, leaving the heavier material 
uncovered in the hollows. 
“Advancing along the channel toward the entrance, it was 
seen that the ripple-marks maintained their parallelism and that 
their section gradually diminished. The same is true in the open 
sea, the undulations there are parallel to those in the channel. 
Alternating zones of heavier and lighter material can always be 
distinguished and they may be easily seen, when the sea is calm, 
at depths of at least 20 metres. 
“Proceeding farther out to sea and making soundings with a 
lead charged with tallow, it was found on raising the lead that the 
zones above referred to were stamped on the tallow. .Sometimes 
a uniform zone of heavy material was brought up and the tallow 
had a convex surface or, again, a zone of light particles was 
brought up when the tallow had a concave form. Finally, at 
great depths, two narrow zones of fine particles of different 
specific gravities were brought up together and it was noted that 
the heavier particles covered a protuberance in the tallow and 
the lighter, a depression. 
“These considerations have led us to recognize that, where 
our observations were made, the motion of the sea makes itself 
felt at greater depths than have been recorded by previous 
observers, who have worked in a less precise way. 
“We regret that time and circumstances prevented us from 
making further research, for the nature of the bottom in which 
we were working was favourable for such observations because 
of its being made up of materials of different specific gravities 
and of different colours. 
“The deepest sounding which has been definitely recorded 
was one of 188 metres (578 feet) made in St. Paul channel on a 
basaltic sand and gravel bottom. In this case the occurrence of 
zones was recognized by the clearest evidence. 
“Soundings were made also at much greater depths, but 
while the results seemed to us to be in all probability analogous 
