Camb. Phil. Soc. Proc, Vol. xi., Part vi., Plate vi. 



*<,**..<-£»&,** * 



I 



Explanation. 



The numbers give the depth in fathoms. The letters m, s, r 

 indicate the character of the bottom, i.e. mud, sand, rock. A, B, 

 D, E are points referred to in the text. 



To face p. 493 



