372 J. w. BEws. 



be at once determined by the presence of certain scrub-filled 

 hollows on the flanks of the ridges in contrast to the barer 

 and smoother slopes of shales above and below. 



The most important feature, however, of the coastal belt is 

 the mantle of blown sand that almost invariably conceals the 

 geological structure over a tract extending inland a distance 

 of from half a mile up to two or even three miles from 

 the shore. Inland this covering is scanty and confined to 

 the ridges, but upon approaching the shore the mantle 

 becomes thicker and more continuous, so that the nature of 

 the underlying strata can only be gathered from scanty 

 exposures along the stream courses, though sometimes for 

 intervals of over a mile there may be no outcrops. 



Along the beach and occasionally bordering the lagoons 

 there are practically continuous surfaces of rock to just above 

 high-water mark, behind which the sand builds up one or 

 more tiers of scrub-covered dunes. These are generally low, 

 the sand being drab or grey in hue with occasional shells or 

 shell-frao-ments, but inland it forms hills rising; to 300 or even 

 up to 400 ft. over the sea-level, and is grey, chocolate, 

 or deep or even bright red in colour. Where the larger 

 rivers pass through the littoral zone such sand is generally 

 missing on the sides of the main valley. 



One of the peculiarities of the coastal belt, namely, the 

 lagoon-like termination of the rivers, has resulted from a 

 recent downward movement of the continent by which the 

 mouths of the rivers have become " drowned '' ; this sub- 

 sidence probably exceeded 150 ft. Following thereon the 

 submerged river-mouths, along Avith their smaller side- 

 streams, have become silted-up, thereby producing embayed 

 alluvial flats bounded by abruptly rising hills, while the 

 main stream feeds a lagoon nearly or entirely cut off from 

 the ocean by a bush-covered sand-spit. In the majority 

 of instances the spit has grown out from the north-eastern 

 side of the valley and terminates opposite a reef of rock that 

 forms the south-eastern side. 



This silting-up action along the depressed shore-line has 



