Characteristic tidal circulation in a canal, a fiard and a fiord is shown and it is indicated that the depth of tidal circulation in those inlets having a threshold probably varies inversely as the temperature of the circulating waters. A series of tidal observations indicated the presence of a semi-daily tide cycle in the surface waters and a daily tide cycle in the deep waters of the sea adjacent to the sound. Evidence of the upwelling of deep ocean water along the coast is shown by the oxygen content. A zone of photo-synthetic activity between 3 and 6 metres depth is outlined by the occurrence of chemical anomalies.