Figure 1. — Stream controlled by Joint Structure 



This stream has its course controlled by joint structures, as is well displayed in the canyon vvalh 

 Frybro, Gudbrandsdalen, Norway. (After a photograph by Knudsen, of Bergen) 



Figure 2. — ;Model illustrating Block Movements within a faulted District which exhibits 



Elements op the Primary Pattern 



Composite blocks of three different orders are shown, as are also the variations in throw on faults, 

 best on the large medial fault of the model 



AN EXAMPLE AND A MODEL OF A FRACTURE PATTERN 



