485 
direction of the axes of the foldings is tolerably regular , being ge- 
nerally about N. 22 deg. E. (true), thus differing from the general 
direction of the dividing range by 33 degrees. At the same time 
it is important to observe that the rule which has been found to 
prevail in other mountain chains of similar formation , appears to 
hold good also in the central chain, viz., that the greatest amount 
of denudation lias taken place along the original ridges which are 
now occupied by valleys , whilst the existing peaks and ridges are 
on the sides of former depressions. 
The next feature to be noticed is the jointed structure of the 
rocks. Although the joints cross each other in all directions, ap- 
parently without order, there are two prevailing systems of joints, 
which have an important influence on the configuration of the sur- 
face. These are: first, a system of vertical cross joints at right 
angles to the stratification and running in unbroken lines for great 
distances with such regularity that they might easily be mistaken 
for planes of stratification, were it not for the frequent occurence of 
beds of trap rock, the outcrop of which marks unmistakeably 
the true bedding; secondly, a system of joints more or less inclined 
to the horizon, not running in parallel planes but arranged in a 
series of curves radiating from a common centre. 
The effect of this system of jointing combined with the strike 
of* the beds or the direction of the axes of folding is to produce 
two distinct systems of valleys in the central chain, the direction 
of which i very remarkable. The one radiates from a common 
centre, situated about 50 miles North of Mount Darwin in the 
sea near Cliffy Head. This system includes all the principal val- 
leys, from the Teramakau on the North to the Makarora on the 
South, their direction varying from N. 82° E. to S. 30° W. , giving 
the idea that the country has been starred , just as a mirror is 
starred by a violent blow; or, as in rock blasting, a set of radiat- 
ing fissures is sometimes produced by a single shot. To the other 
system belong the valleys of rivers and watercourses running either 
on the strike of the beds or in the direction of the cross joints, or 
in a compound zigzag course , following alternatly these two direc- 
