102 
SYMPOSIUM PHOTO INTERPRETATION, DELFT 1962 
Section A-A' 
Topography estimated from aerial photographs 
A” Repeated rr 
Information from air photographs 
Strike. Strike and dip 
Fig. 1. 
Photogeological Map of the Mahenge Syncline, Tanganyika 
This map of an area of regionally metamorphosed rocks was produced by photogeological 
interpretation checked by reconnaissance field work. (Based on sheet D.O.S. (Geol) 1130 
Directorate of Overseas Surveys) 
specific rock types could be made. After four months’ reconnaissance field 
work by two photogeologists (Mr. R. L. Birch and the author) it was possible 
to delineate the rocks photogeologically to the standard achieved by normal 
ground mapping, and the final maps have been published as Sheets 250 and 
251 of the Geological Survey of Tanganyika, Quarter Degree Sheet series.