418 
SYMPOSIUM PHOTO INTERPRETATION, DELFT 1962 
diagram with it (fig. 4a) gives the interpretation. Together with a plan based 
on vertical air photographs, it would provide us with the answer to a difficult 
problem, and once more shows how much this study of ancient fields is quite 
dependent on air photographs. We can never have too many of them. 
Acknowledgement 
The author would like to pay grateful acknowledgement to Dr. St Joseph 
and the British Royal Air Force for permission to make use of invaluable air 
photographs and to the Royal Commission on Historical Monuments (Eng.) 
for letting him draw on information in its files.