Cotton. — Notes on Wellington Physiography. 255 



while the smaller ravines are truncated, appearing as notches, hanging 

 at various heights on the cliffs. Wherever the lower reach of a stream 

 makes a small angle with the coast the spur separating it from the sea 

 has the form of a razorback, due to lateral cutting by the stream on 

 one side and the sea on the other. 



The coast-line is, therefore, a continuous line of stupendous cliffs, 

 rising in places on the south coast, where the coast-line cuts across the 

 highest ridges, to 700 ft. or 800 ft. In Plate XIX, fig. 1, a portion of the 

 south coast is seen eastward from Sinclair Head. The triangular cliff- 

 facet photographed is 400 ft. or 500 ft. in height. To the west the height 

 of the cliffs increases. 



The Coast Platforms. 



Along parts of the coast no relics remain of elevated platforms cut 

 by the sea during pauses in the movement of uplift. They have either 

 been completely cut away by the waves or cut off by faulting along 

 new lines of fracture. At other places extensive 

 shelves remain. The most prominent begins at 

 Tongue Point and extends some distance west- 

 ward (see fig. 7, and Plate XVIII, fig. 3). The 

 shoreward edge of this shelf appears to indicate _^-~-^/>-^-- r ~ ' ^-> 



..^^^laiiii^^ 



Fig. 7. — The Elevated Coast Platforms at Tongue Point. 



the base-level at the time when the streams of the district developed the 

 greater part of the existing upland topography. For that reason the writer 

 has named that erosion cycle the Tongue Point cycle. 



The height of the shelf at its inner edge at Tongue Point is 240 ft. 

 Its slope seaward is at first 10°, but rapidly decreases, and at the 

 end of Tongue Point, where the shelf is half a mile broad, it runs 

 gently out at an angle of 2° or 3°. 



The upper surface of the shelf is covered by a veneer, 6 ft. or 8 ft. 

 in thickness, of gravels similar to those of the present beach. They 

 vary irregularly from beds of coarse roughly rounded gravel and 

 boulders, material similar to what is being supplied to-day in large 

 quantities by the smaller streams, to layers of fine flattened discs of 

 beach-shingle varying from the size of a threepenny-piece to that of a 

 penny. Jl layer of the coarser gravel is seen on the right in Plate XVIII, 

 fig. 3. 



The varying height of the outer scarp of this marine terrace as 

 seen from the sea is clearly due mainly to the varying breadth of the 

 portions that have withstood the action of the sea, the seaward slope 

 of the shelf being regarded as nearly constant. At the extremity of 

 Tongue Point it comes down to 170 ft. Beyond the next creek to the 

 west, where there is a well-preserved but narrower remnant, the outer 

 edge bounded by the present scarp is, as might be expected, higher. 

 It is evidently this apparent variation in the height of the shelf that 



