Fig. 11 
  
MERSEYSIDE AREA DATA VERTICAL STRATA 
sate: 
agra: 
évoli 
trio 
du c 
exem 
rie 
nage 
  
  
  
  
1/10 
La co 
joign 
COMPUTER-DRAWN MAPS 
On pe 
KEY (Values divided into 5 equal value classes) 140? 
An chemi 
5 (Highest) 
moine 
4 
2.2. 
  
L'uti 
1 (Lowest) graph 
cédem 
nehau 
soumi 
plus 
A l'é