AUSTRALASIA, NEW GUINEA, AND NEW ZEALAND 767 



Britannica suggests that this island group was built principally as 

 from southwest to east and north, or at any rate that with the prog- 

 ress of geological time folding movements retreated to the north 

 by east. Marshall, however, in a personal communication, under 

 date of April, 1916, states that much of the New Zealand Jurassic 

 has been confused with the Maitai (so-called Carboniferous) by 

 older workers. Marshall, however, adduces sound reasons for 

 considering New Zealand as being the true boundary of the Pacific 

 Ocean 1 in that portion of its area. Cotton in a recent paper states 

 that the "most profound deformation of this vast sedimentary 

 group [Paleozoic and Mesozoic] took place in Later Jurassic or 

 Early Cretaceous times." 2 He also states that the average trend 

 of the strike of this older mass appears to be west of north (p. 245). 

 And again he writes: "It is apparent that during the period of their 

 deposition [that is, the Tertiary Andes] a great part of the site 

 of the present islands of New Zealand was continually submerged" 



(P- 247)- 



Cotton also speaks of orogenic movements in the Pliocene in the 

 northern and more eastern portion of the group, and it is known, 

 moreover, that great volcanic activity has taken place in the 

 northeastern portion of the group with the formation of important 

 gold deposits. 



In a personal communication dated August 22, 191 6, Cotton 

 writes : 



The early geological history [of New Zealand] is much obscured by the 

 later happenings — a great deal more so, it would appear, than is that of 

 Australia. We cannot even be sure that we have any considerable area of 

 Paleozoic rocks. The small areas of Ordovician and Silurian in northern 

 Nelson we can be certain of, but we know nothing whatever of the relations of 

 these, either to each other or to rocks of later Paleozoic or Mesozoic age. It is 

 the opinion of the present director of the Geological Survey that the greywacke 

 rocks extending southward along the West Coast are of Aorere (Ordovician) 

 age; but they contain no paleontological evidence of age and are part of the 

 "Maitai" system of other writers. As for the "Maitai" rocks throughout 



1 P. Marshall, "Presidential Address," Geological Section Aust. Assoc. Adv. Set. 

 Sydney, XIII (191 1), 90-99. 



2 "The Structure and Later Geological History of New Zealand," Geol. Mag. Lon- 

 don, No. 624, June, 1916. 



