94 



Transaction a. 



General Topography. 

 (See map, fig. 1.) 



The chief stream of the Hurunui rises in the main chain of the Southern 

 Alps, and flows east between bush-clad mountains whose height approxi- 

 mates between 5,000 ft. and 6,000 ft. till after a straight course of some 

 eighteen miles it empties into Lake Sumner. This is a fine lake, seven miles 

 long by one a half wide in its widest part, 1,724 ft. above sea-level. Thence 

 the Hurunui flows south-east for about eight miles, and receives on the 

 south a tributary almost as large as itself, called the South Branch, the 

 main stream being sometimes called the North Branch. In this part of its 

 basin are several small lakes, the most important being Lake Katrine 

 (which is practically an indentation near the head of Lake Sumner), Lakes 

 Taylor (1,914 ft.) and Sheppard (1,916 ft.) in a valley between the two 

 branches, and Lake Mason in a side valley of the South Branch. 



Below the junction of the two main streams the valley continues for 

 nearly three miles in a south-easterly direction between somewhat pre- 

 cipitous mountain-sides, and then turns east and passes through a deep, 

 narrow, picturesque gorge, locally known as Maori Gully, and believed to 

 be the scene of an engagement between two Maori tribes in early days. 



tRobinson 

 JBlythR. 



FAULT L//VES 



AXES OF FOLDING _ _ _ 



Fig. 1. — The Hurunui Valley. 



The river then flows north-east for nearly ten miles through a hilly region 

 in a narrow channel cut in the floors of detached basins and deeply incised 

 in the ridges dividing them, till it reaches the Mandamus River. 



Just below the junction with this stream the direction of the main river 

 turns through a right angle and it enters the Hurunui- Waiau basin, flowing 

 for about ten miles through an aggraded flood-plain till it receives the 

 Waitohi on the south. It then makes a sudden turn and runs north-east 

 along the southern edge of the Hurunui Plain, receiving the Pahau River 

 on the north ; but after a course of about eight miles it again breaks through 

 a mountain barrier in a south-easterly direction and receives the Waikari 

 River on the south and the Kaiwara Creek on the north, immediately after 

 which it breaks through yet another mountain barrier and debouches into 

 the Greta-Cheviot basin, across which it flows in a broad bed with terraced 

 banks in an easterly direction till it discharges into the sea after cutting 

 a somewhat deep gorge through a rocky bar just at its mouth. 



The most striking feature of its course as a whole is the peculiar zigzag 

 direction of the reaches which characterizes the middle part of its basin. 

 These zigzags have alternate north-west and south-east and south-west 

 and north-east arms, and it is their special relation to the grain of the 

 country in some places and their absence of relation in others which is 

 peculiar. 



