146 Lecture on the Geology of [No. 9, new sehies. 



5. About twenty-five miles below the outlet of the Waikato 

 from Taupo, at the 4 pa' Orakei- korako, both banks of the rapidly- 

 flowing river are perforated, in more than a hundred different 

 places, by fumaroles and boiling springs, most of which are of the 

 intermittent kind ; and siliceous incrustations of beautiful colours 

 decorate the banks of the river. Temimi-a-Homaiterangi — the 

 principal geyser — throws up its large column of boiling water at 

 intervals of about two hours to a height from 20 to 30 feet. An 

 immense volume of steam succeeds the jet, and the water then 

 suddenly sinks into the basin. 



6. At Orakei-korako the line of hot springs crosses the Wai- 

 kato, and continues along the foot of the very remarkable Pairoa 

 range on the Easterly side of the Waikato. The almost perpen- 

 dicular Western side of this range is caused by an immense ' fault' 

 in the volcanic plateau, corresponding to a deep fissure in the 

 earth-crust, from which sulphureous acid, sulphuretted hydrogen, 

 sulphur and steam, are continually escaping, while huge bubbles 

 of boiling ash-coloured mud are rising on the surface. 



7. From the same range, the warm-water river Waikite takes 

 its origin. On both sides are deep pools of boiling water, on the 

 margins of which we discovered most beautiful ferns, hitherto un- 

 known, one species belonging to the genus Nephrolepis, the other 

 to the genus Goneopteris. These ferns are remarkable not only 

 for their elegance, but also from the peculiar circumstances under 

 which they exist, as they are always surrounded by an atmosphere 

 of steam. 



8. We now come to the well-known Rotomahana, the most 

 wonderful of all the wonders of the Hot Springs district of New 

 Zealand. I will not attempt to describe in a hasty lecture like this 

 the beauties of this Faery-land. Whoever has once had the hap- 

 piness to look into the blue eyes of Otukapuarangi and Te Tarata 

 can never forget their charms ; and whoever has stood beside the 

 boiling surf of the Ngahapu basin will always retain a vivid im- 

 pression of its tenors. The terraces of siliceous deposit on the 

 shores of Rotomahana are unequalled in the world, nor is there any 

 thing that even bears any resemblance to them. 



9. On the Rotorua lake the intermittent boiling springs of Wha- 



