278 Transactions. 



Opposite the right-angle turn of the river referred to above, and imme- 

 diately to the west of the axis of the anticline, there is distinct evidence 

 of the presence of an unconformity between the gravels just referred to 

 and a higher series. The beds here consist of sands and sandy gravels 

 which are lithologically indistinguishable from the higher members of the 

 lower series. On a bluff facing the river the beds in contact with the 

 gravels of the lower series are exposed lying across their denuded edges at 

 low angles, and immediately to the north-west they show a reversal of dip 

 and are inclined to the south-east at angles of from 5° to 7°. This dip is 

 in agreement with that which can be observed in sections in the upper 

 basin of the Southern Kowai, and notably to the south of the anticline 

 which runs to the south-east of No. 2 Creek and parallel with it. Thus 

 there is evidence of an unconformity in the Southern Kowai in close 

 proximity to that in the No. 2 Creek in the drainage area of the Northern 

 Kowai. 



It will be noted that the lowest members of the series present in the 

 two branches of the Kowai consist of sandy beds with marine fossils, 

 whereas these do not appear with certainty in the Grey River. The gravel 

 beds are, however, equally developed in each area. This difference is perhaj)s 

 of no special stratigraphical importance, since the gravel beds in both areas 

 are undoubtedly marine, and in the Grey area conditions may not have 

 been favourable for the preservation of fossil remains. As far as I can 

 see at present, there is no evidence of a major unconformity between the 

 gravel beds and the lower marine beds, although minor, intraformational 

 unconformities undoubtedly exist. There is, however, distinct evidence 

 of a discordance at a higher level in the Kowai series between beds of 

 similar lithological character both above and below the unconformity, 

 but not such a discordance as necessitates the higher beds being placed 

 in another distinct series. The whole area and its vicinity no doubt 

 experienced a fairly rapid elevation, probably of a differential character, so 

 that erosion went on in one part of the area while deposition was continuous 

 in an adjacent part. If subsequent deposition over the denuded area then 

 ensued this special stratigrai^hical feature can be satisfactorily explained. 



Fox's Creek. 



In Fox's Creek, the next stream south of the Kowai, there is an excellent 

 section of the gravels forming the great mass of the downs area. This 

 stream rises in the centre of the area and flows east, being bounded on the 

 north for the middle part of its course by precipitous banks, in places up 

 to 500 ft. in heiglit above the stream. The beds here exposed consist of 

 sandy gravels, sands, and sandy clays, with occasional thin, discontinuous 

 layers of sandy carbonaceous shale. The sands are frequently blue-green in 

 colour, and without fossils as far as I could see. In this part of the course 

 of the stream the beds lie flat, with a slight dip to the north, but on the 

 eastern margin of the downs the dip increases to 10° and its direction 

 becomes south-east. In the adjacent valleys to tlie north and south there 

 are similar beds with similar dip. 



Lower Waipara Gorge. 



Just where the river crosses the western end of the Limestone Range, 

 beds of the Motunau series are exposed, consisting of marine sands, sandy 

 clays, and sandy gravels frequently cemented with calcareous material 

 and containing numerous fossil shells (Speight, 1912 and 191i). They are 



