272 G. A. Cotton — Block Mountains in New Zealand. 



sioiis. Blocks bounded on all sides by faults have not been 

 recognized; most of the bonndarj faults diminish in displace- 

 ment and are evidently replaced by flexures (fig. 13). 



Towards the southwest, owing to diminishing displacement 

 on the faults and flexures bounding them, the depressions are 

 no longer distinguishable. With the mountain blocks they 

 merge into a high, broken plateau, in which detailed investiga- 



FiG. 13. 



Fig. 13. Generalized diagram of the Central Otago chain of depressions 

 and the associated block mountains. D, Dunstan block ; M, Maniototo 

 depression ; R, Eaggedy-Blackstone block ; IV, Ida Valley depression ; ER, 

 Rough Ridge block ; Mo, Maniototo depression ; HP, Rock and Pillar block ; 

 T, Strath Taieri depression and Taieri River ; P, Barewood Plateau ; B, St. 

 Bathans block ; H, Hawkdnn block ; I, Mount Ida ; C, Clark's Diggings 

 fault angle ; K, Kakanui block ; S, Shag Valley fault angle ; CI, Clutha 

 River, 



tion doubtless will reveal the presence of a number of distinct 

 blocks. 



Towards the northeast, on the other hand, the crests of the 

 mountain blocks slope down so as to merge more or less com- 

 pletely in the lowlands and form a chain of nearly continuous 

 depressions, which is a fault angle between the northeasterly 

 slope of the southern block-complex and a great scarp with a 

 general northwesterly trend, or a series of scarps broken by 

 several offsets, which forms the boundary of a northern com- 

 plex of high blocks. 



In the latter fault-block complex, which may be termed the 

 nortiicrn highland of Otago, the general trend of the disloca- 



