3*24 GEOLOGICAL CHARACTER [PART II. 



was obliged to descend into the deep channel which 

 it had dug out of the soft tufaceous and leucitic 

 lava. The banks which form its channel during 

 freshes are about 150 yards distant from each other, 

 but now the river was confined between banks of 

 six feet high, and within much narrower limits, not 

 being more than fifty yards broad. Its course was 

 from S. by E. to N. by W. In some parts it was 

 deep, and at others it formed rapids ; the water was 

 bluish and clear, and marked the near neighbour- 

 hood of the snows and glaciers of the Ruapahu, in 

 which it takes its rise. 



We had a distant view of Horo Horo, a moun- 

 tain in which the river Thames has its source ; it 

 bore S. 80 E. We also saw Titiraupena, a py- 

 ramidical mountain, with naked black rocks heaped 

 upon its pointed summit, and bearing S. 20 E. 



On the 5th and 6th we passed through a coun- 

 try in the highest degree curious to the geologist. 

 It was broken into a number of hillocks, most irre- 

 gularly dispersed over the perfectly level surface of 

 the original table-land. On the hillocks them- 

 selves most regular terraces were visible in some 

 places, and it was plain that they could have only 

 been produced by a gradual fall of the waters. All 

 these hillocks consisted of tufa, or the before-men- 

 tioned lapilli of pumicestone, cemented together. 

 Everywhere flowed little streamlets, and we passed 

 two deep creeks, the Maunga Wio and the Wai- 

 papa, tributaries of the river Waikato. The Wai- 



