L ay. Soc.Edxa r Tol.ZZXn 



Plate 6. 



THE CLYDE SEA- AREA 



Surface Water Density 



Average 1886-1887. 

 MAX. MEAN, MIN. 



THE DARKEST TINTS OF 6REEN, INDICATE GREATEST MEAN OEMSITY. 



JdhnBarQioloiiisw & C( 



