VOLUME XXX NUMBER 1 



THE 



JOURNAL OF GEOLOGY 



y anuary-February ig22 



AN OUTLINE OF THE GEOLOGY OF NEW ZEALAND^ 



W. N. BENSON 

 University of Otago, Dunedin, New Zealand 



Pre-Silurian. — In the more recent accounts of the history of 

 New Zealand it has been customary to consider as of Pre-Cambrian 

 age the complex of gneisses and associated metamorphic rocks in 

 the southwestern extremity, but the evidence for so doing is not 

 yet conclusive, and various authors have referred the plutonic 

 gneisses therein to different periods, extending as late as the Creta- 

 ceous. It would appear that the more probable hypotheses could be 

 limited to two. 



The first definite point lies in the proved existence of Lower 

 Ordovician rocks in the extreme northwest and southwest of the 

 South Island (Fig. i).^ These grap toll tic slates are associated 



' This outline is based on the writer's presidential address delivered to the geo- 

 logical section of the Australasian Association for the Advancement of Science in 

 1 9 2 1 . For detailed discussion of the most recent work, with full bibliography, reference 

 may be had to this address. Earlier extensive accounts have been given by Marshall 

 ("New Zealand and the Adjacent Islands," Steinmann's Handbuch der regionalen 

 Geologie, Bd. VII, Abt. i, 1912), and Park (The Geology of New Zealand, Whitcombe 

 and Tombs, 1910). 



' The map herewith (Fig. i) has been based upon one recently issued by the 

 Geological Survey (see New Zealand Journal of Science and Technology, 192 1) and 

 also incorporated in the above-mentioned address, thanks to the generous permission 

 of the director of the geological survey, Mr. P. G. Morgan. The present copy has 

 been somewhat modified in accordance with the view favored herein concerning the 

 age of the Otago schists, etc. 



