134 W. H. HOBBS REPEATING PATTERNS IN STRUCTURE OF LAND 



sign — will in a broad way be indicative of the precipitation of the dis- 

 trict, the branchings showing wider space intervals in the less humid 

 district. 



Figure 9. — Emhrasure-like Notching of the 

 Coastline of West Greenland 



This notching is due to control by the 

 fracture system of the district. (After Kor- 

 nerup) 



Figure 10. — Normal Drainage 

 Network ahove homogeneous 

 Rock devoid of Structure Planes 



STRUCTURAL CONTROL OF NETWORKS 



Variations from the normal network may be toward a largely lawless 

 or haphazard system, such as may sometimes be seen in regions where rock 

 is buried deep under drift deposits. On the other hand, a definite pat- 

 tern in repeating diapers will be betrayed wherever the structure planes 



Figure 11. — Illustration of structural Control of Network 



The view shows a narrow cleft in well jointed rock widened at top and bottom, within 

 which talus is being removed by an outlet glacier, and the cleft extended headw^ard by 

 the same influence. East wall of the Sermiarsut glacier. (After von Drygalskl.) 



