Cussen. — Notes on the King Country. 321 



elevations on the ranges, but when seen in the deep worn beds 

 of the stream, near the base of the mountains, they are in large 

 compact rock masses. 



Tertiary Formation. 



To this formation, I believe, belong the clays and limestones 

 of the Mokau Valley. Hochstetter says : " The bottom of the 

 Mokau Valley is composed of tertiary clays, impervious to water ; 

 while at the slope of the hills tabular limestones protrude, the 

 heights themselves being formed of trachyte tuff." 



These tertiary limestones occupy an area of about 200 square 

 miles in the valleys of the Mokau and Mangapu. In the Mokau 

 Valley they seem to have occupied an area of depression, 25 

 miles in length from north to south, and about 8 miles in 

 width, surrounded by high hills, 1,200 to 1,800 feet above the 

 sea. The limestone beds have undergone immense denudation ; 

 they stand out on the sides of the valleys in picturesque detached 

 masses, resembling the ruins of old castles and fortifications, 

 frequently occupying positions 300 feet above the level of the 

 valley, the peculiar slab-like weathering of the laminated masses 

 making them look like the remains of ruined masonry. The 

 colour of the limestone on the surface is white, probably owing 

 to weathering, but it passes into a compact mass of bluish fine 

 grained rock underneath. 



The tertiary limestones occur also on the Marakopa River, at 

 Te Anga, 20 miles inland from the mouth of the river. They 

 are seen here in picturesque columnar rocks, cleft and worn into 

 many shapes and forms, and forming long high walls along the 

 river sides. At Rakau-nui River, Kawhia Harbour, there is also 

 a great development of the limestone formation. Here it forms 

 interesting landscape scenery, in picturesque islands and pro- 

 montories ; portions of the rock masses being dislodged and tilted 

 up in the process of denudation, look as if they were disturbed 

 by violent volcanic action. All this limestone formation is noted 

 for its numerous caves, underground watercourses, funnel-shaped 

 holes, and overhanging rock ledges. The caves were, in former 

 times, no doubt shelter caves and sleeping places of the moa, 

 and in years gone by their bones were found in the caves in large 

 quantities. They have, however, long since disappeared, and we 

 were never fortunate enough to find any relics of the moa in the 

 caves. 



Lying to the eastward of the limestone area of the Mokau 

 Valley is an elevated plateau, which rises gradually in an 

 easterly direction, or towards Taupo. The general height of 

 the plateau above the sea is from 1,500 to 2,000 feet ; it is divi- 

 ded by deep water- worn gullies into long winding spurs. This 

 plateau extends from the slopes of Rangitoto Mountain south- 

 wards for a distance of about 30 miles, and it has an average 



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