REPORT OF COMMISSION VII 
GVII-29 
Area: 348 linear miles 
Types and scale of photography: Ektochrome, 1:10,000 scale vertical photog 
raphy, 12" 
Pi instruments used: Stereoscopes, stereometers 
Types of information furnished: Eventual research paper 
Title: Swan Lake, Alaska (research) 
General description: Photogeologic mapping of a small area proposed as a 
dam site 
Dates: Begun and finished 1955 
Area: 200 square miles 
Types and scales of photography: 1:40,000 scale, vertical, 6" photography, 
black and white 
PI instruments used: Kelsh plotter 
Types of information furnished: Structural setting in vicinity of dam site. 
Area heavily vegetated. Results not yet field evaluated 
Title: Salt Chuck mine area and Hollis mine area, Alaska (research) 
General description: Photogeologic mapping of small areas adjacent to certain 
copper and gold mines, igneous metamorphic terrain 
Dates: begun and finished 1955 
Area: 45 square miles 
Types and scale of photography: 1:40,000 scale, vertical 6" photography, 
black and white 
PI instruments used: Kelsh plotter 
Types of information furnished: Structural setting (faults and shear zones) 
in vicinity of mines. Area heavily vegetated. Results not yet field evaluated 
Title: Prince William Sound area, Alaska (research) 
General description: Mapping of regional structural setting in igneous- 
metamorphic terrain 
Dates: Begun 1953. This is a continuing project 
Area: 4,000 square miles 
Types and scale of photography: 1:40,000-scale vertical, 6" photography, 
black and white 
PI instruments used: Stereoscope, stereometer 
Types of information furnished: Detailed fracture pattern in an area of former 
copper mining activity. Area heavily vegetated. Results not yet field evalu 
ated 
TYPES OF PHOTOGRAPHY USED IN GEOLOGIC INTERPRETATION 
The geologist-photographic-interpreter frequently works for reasons of 
economy, with whatever photography already exists in the region with which he 
is concerned. However, as a result of research into the effectiveness and limita 
tions of various types of photography for geologic purposes, ideas of geologists 
as to desirable types and scales of photography are well developed. These ideas 
may change with the individual, and will certainly vary with the particular type 
of geologic problem to be solved, but the general requirements are fairly consist 
ent. 
In papers presented at a symposium on photogeology sponsored by the U. S. 
Research and Development Board in 1953, some comments on photographic re 
quirements were made by two experienced photogeologists, Mr. R. F. Thurrell, 
Jr., and Dr. F. A. Melton. Since this is believed to represent perhaps the best