MECHANICS OF FORMATION OF ARCUATE MOUNTAINS 89 



B 



Fig. 8. — Apparatus for the simulation of mountain arcs through the contraction 

 of locally rigified films of plastic material. A. View of frame with metal triangle in 

 extended position. B. The same with sheet of rubber supporting a layer of Canada 

 Balsam which was poured hot and when the fubber sheet was stretched, but was 

 locally rigified and then forced to contract upon the relief of tension in the rubber. 



