348 Transactions. 



towards the north-west, the limestone, although continuously linked up with 

 the Weka Pass stone, being deposited synchronously with the Mount Brown 

 stone. 



(3.) The limestones are followed by sands and gravel beds with bands 

 of conglomerate composed almost entirely of greywacke. These are well 

 developed in the Isolated Hills, where the stratification is much disturbed. 

 They occur with regular dip to the south-east at Mouse Point, near Cul- 

 verden, accordant with that of the underlying limestones ; but they are 

 folded into a well-marked anticline at Hurunui Mound ; and they form 

 low hills on the south side of the Hurunui, which extend towards the Wai- 

 para River along the eastern side of Mason Flat, and divide that part of 

 the basin from the upper part of the Waikari Valley. These beds overlie 

 the limestones conformably on the western end of the Alexander Range. 

 On following the line of outcrop west past Hawarden and Horsley Downs, 

 the dip becomes very steep to the west till on reaching the Doctor's Range 

 of Trias-Jura rocks the dip is nearly vertical. This part of the basin appears 

 to be formed of beds arranged as a syncline, with the eastern limb much more 

 highly inclined than the western, a feature which appears to be almost 

 invariably exemplified, for the eastern edge of these basins is determined 

 by lines of faulting grading into steep folds. Similar arrangements of the 

 beds occur in the Omihi Valley, in the Lower Waipara, which has its south- 

 eastern margin bounded by a fault, but it is not seen in the Cheviot basin, 

 which lies between the Waiau-Hurunui basin and the sea, being divided 

 from the former by a range of older rocks and from the latter by a similar 

 range, but the limestones pass right over this range without any marked 

 signs of faulting or break. The arrangement of the beds in the Cheviot 

 basixi is synclinal, but as the Tertiary strata are followed south-west they 

 exhibit faulting which accounts for the characteristic strip of let-down 

 Tertiaries which occupy the valley of the Greta Creek. 



The lithological and faunal evidence indicates clearly that land existed 

 in the neighbourhood of this area at the beginning of the cycle of deposi- 

 tion ; that the sea gradually extended over the area, followed by the shallow- 

 ing of the sea and the deposition of littoral beds. These have been 

 subjected to folding movements in which the underlying Trias- Jura beds 

 are involved, so that the form of the land-surface on which the Tertiaries 

 are laid down is quite different from that which now exists, but there is 

 distinct evidence of the close proximity of land throughout the period of 

 deposition. There is no sign, however, of any erosion of the underlying 

 beds while the later ones were being deposited, judging from the absence 

 of pebbles of limestone in the later deposits, so that it is unlikely that the 

 movements to which the rocks have been subjected had commenced during 

 the latter part of the period of deposition. Owing to erosion of the rela- 

 tively weaker Tertiary beds, a large area of these rocks has been removed ; 

 but it is extremely unlikely that they extended over the whole area. 

 Isolated peaks of Trias-Jura rocks no doubt existed as islands in this sea, 

 but they were by no means as extensive as the present areas of mountains 

 composed of these rocks. The basins have no doubt had an origin in 

 deformational movements either of folding or faulting, both of these move- 

 ments being closely related to each other. 



Hanmer Plains. 



This inland basin has generally been regarded as of structural origin, 

 even Hutton admitting this as being extremely probable. That earth- 



