54 

 Plant. Part of the increased temperature may also have been 

 due to the formation of slow moving gyrals in the southern 

 portion of the bay and a consequent increase in local water 

 temperature from solar heating alone. 



Below these two subunits were several patches of water of 

 varying temperature that form an intermediate zone between the 

 Surface and Subsurface Units. These were sufficiently developed 

 to be treated as more than a transitional subunit. 



The Subsurface Water Unit was composed of several broad 

 strata ranging downward in temperature from 53° to 48°F. The 

 main temperature differential between surface and subsurface 

 water amounted to about 10° at an average depth of 55 feet. 

 The subsurface water gave some indication of progressively 

 higher temperatures in an inshore direction, perhaps indi- 

 cating motion of water at most depths over the shelf toward 

 shore. It is interesting to note that the coldest water and 

 the warmest water occurred together during the summer months. 

 This cool contribution may have been the result of several 

 processes including internal waves and upwelling offshore, both 

 of which would have introduced cooler water into the deeper 

 portions of the shelf water mass . 

 July 1955 



The thermal characteristics of the various water units 

 and subunits in July 1955 were similar to those in June 1955, 

 except that surface temperatures reached 68°F (Fig. 16). Many 

 more patches of water appeared in the surface unit during this 

 month and the base lay at an average depth of 40 feet. The 

 surfaces were much distorted in their finer details, perhaps 



