PHYSICAL OCEANOGEAPHY OF THE GULF OF MAINE 



935 



is the stronger. But if the bottom current be the stronger, and both currents are 

 opposite or diverge by a considerable angle (as may rarely be the case in shoal water, 

 though perhaps never in deep), the method is made unreliable. 



Fig. 187.— Distribution of density at tlie surface, February to March, 1920 



In studying the dynamics of any shoal area it is also essential to appreciate 

 the effect which the contour of the bottom may have in deflecting the gradient 

 currents. This, of course, can not be stated by rule, but usually it is fairly simple of 

 interpretation. 



