THE GEOLOGY OF NEW ZEALAND 



east of the broad anticlinal axis, which 

 reaches the sea near Dunedin. To these 

 rocks all ages have been assigned from 

 Archaean to Jurassic. They are not as- 

 sociated with plutonic rocks, but may 

 be traced outward from a central zone 

 of maximum schistosity, through gradu- 

 ally decreasing metamorphism into 

 graywackes indistinguishable from the 

 Ordovician or Lower Mesozoic gray- 

 wackes. The Geological Survey and 

 the majority of other authorities hold 

 that the schists are ancient and must 

 be separated by obscure disconf ormities 

 from the Mesozoic rocks. Marshall 

 considers the schist Mesozoic, and, after 

 much hesitation, the writer inclines 

 toward a modification of this view. In 

 this it is suggested that the flat arch of 

 metamorphic rocks is the base of a great 

 series of recumbent folds of late Paleo- 

 zoic and Lower Mesozoic rocks which 

 were pressed against a resistant or con- 

 tinental mass now concealed beneath 

 the southern portion of the island. In 

 the front of such a series of recumbent 

 folds one would expect to find a sharp 

 fourfold-wrinkle of the crust, beyond 

 which the thrusting would die away in 

 gentle undulations of the strata lying 

 on the resistant mass. Within the 

 overfolded areas, block-faulting might 

 bring down the comparatively unmet- 

 amorphosed rocks of the higher recum- 

 bent folds into close apposition with 

 the more schistose rocks of the lower 

 folded sheets (Fig. 2). These expecta- 





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