CHAPTEK XII. 



TEKTIAEY AND KECENT DEPOSITS. 



IN many parts of the Colony there are accumulations 

 of sand, gravel, alluvium, limestones, quartzites, and 

 ferruginous rocks that belong to a comparatively recent 

 order of things, and in some cases are to-day in process 

 of formation. There is invariably a marked uncon- 

 formity between those rocks and the strata upon which 

 they rest, although it is not always easy to find a suit- 

 able exposure of the junction. 



The age of these beds can only be determined by the 

 fossils contained in them, though their position with 

 regard to the present level of the sea and that of rivers 

 near them is of considerable value in this connection. 

 Up to the present time but few fossils have been col- 

 lected from these beds, and of those obtained only a 

 small number have been studied by palaeontologists. 

 It is extremely probable that some of these formations 

 contain species of mollusca that are no longer living ; 

 others have yielded bones of mammals belonging to ex- 

 tinct species ; but details which will serve as the basis 

 of a chronological classification of these deposits are 

 not yet available. 



In the following account the deposits will be chiefly 

 classified on lithological and topographical grounds, 



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