Fauna and Flora of New Zealand. 91 



in 1875 he said that " he thought that the effects of glacial 

 action had been immensely exaggerated, and believed that all 

 the great features of the country existed before the glacial 

 period ; " * and in the following year, in his paper on the 

 history of the river Dee, he says that " by far the greater 

 part of the valley-excavating work was performed between 

 Permian and Pre-glacial times, and that the work of the 

 glaciers of the latter period somewhat deepened, widened, 

 smoothed, and striated the outlines of the mountains and 

 valleys, and excavated many rock-bound lake-basins, but on 

 a grand scale did not effect any great changes in the pre- 

 existing larger contours of the country " f . 



In our own case we must remember that, even if glacier 

 erosion is as great as claimed by the advocates of the plateau 

 hypothesis, there have been in New Zealand, in the Lower 

 Cretaceous and Eocene periods, two earlier and probably 

 quite as extensive glacier epochs, which must have reduced 

 to ridges the supposed plateau, if it ever existed. We must 

 also remember that the New-Zealand Alps have been under- 

 going subaerial denudation without interruption from the 

 Jurassic period to the present day ; and we have conclusive 

 proofs that most of the valleys had been hollowed out nearly 

 as deeply as now in the Eocene period, because we find all 

 the large river-basins partly filled with Oligocene, or, in some 

 cases, even with Upper-Cretaceous rocks. I will limit myself 

 to one example in illustration. In the middle Rakaia, on the 

 right bank of the river opposite the south end of Lake Cole- 

 ridge, there is an outlier of Oligocene Limestone, called Red 

 Cliff. It is lying in its original plane of deposition, and is 

 no doubt a fiagment of a set of beds which once filled all this 

 part of the valley. At present it is restricted to a patch 

 occupying a sheltered side valley on the south side of the 

 river ; but it again appears at the river-bed as an apparently 

 detached fragment separated from the main mass in the valley 

 by river-gravels. This isolated portion is known as Castle 

 Rock. Now the first thing to be noticed is that this Oligo- 

 cene limestone descends to below the present level of the river, 

 proving conclusively that the Rakaia is now running at a 

 higher level than it did in the Eocene period before the lime- 

 stone was deposited. The second thing to be noticed is that 

 the junction up the side valley between the limestone and the 

 Palaeozoic rocks on which it rests must mark the limit of the 



* Quart. .louru. Geol. Soc. xxxii. p. i'04. 



t Quart. Journ. Geol. fSoc. xxxii. p. 227. See also l»r. Kniglit, in 

 Trims. N. Z. Inst. vii. p. 47i>. 



