Scattering Layers — Bary 
177 
Fig. 7. Anomalous behaviour of a scattering layer 
during darkness. At first it is descending deeper into 
the water, and then begins to rise again. The phasing 
of the sounder has displaced the transmission signal 
down the fathogram; "Lachlan” record, L3. 
shown in Figure 8. The dense shoal (marked 
"Fish?”) would appear from its uneven dense- 
ness and patchiness, to be a large fish shoal, 
which then extends at lesser concentrations 
more or less parallel to the bottom. In view 
of the subsequent history of this zone of 
scattering — the record is continuous with that 
in Figure 8— it is possible that other pelagic 
organisms are contributing to it as well. 
Fig. 6. A scattering layer maintaining a fluctuating 
daylight level in moderately deep water over the 
Chatham Rise; "Galathea” record, G4. 
