228 Transactions. 



calcareous sands with concretionary bands, and gravel -beds more or 

 less cemented, and are highly fossiliierous. The chief genera to be col- 

 lected are Mactra, Ghione, Ostrea, Pectin, Crepidula, and also Bryozoa . 

 Some beds are almost wholly formed of the remains of Crepidula, but 

 they are usually in a poor state of preservation. A characteristic 

 feature of the beds at this point are the massive bands of coar.e cemented 

 gravels, dipping to the west at an angle of 60°. For a long distance 

 one of these beds forms one bank of the river, and it can !>e traced some 

 distance to the north-east on the north side of Mount Cass. Here it 

 dips at a steeper angle, and on going further it is apparently lost 

 under the covering of soil. In all possibility it will reappear in the 

 creeks which flow from the northern side of the Limestone Range. 



The same direction of dip and strike is approximately maintained 



on following down the river to the immediate neighbourhood of a 



pronounced meander of the stream. The strike here begins to swing 



round in a positive direction, so that, while just above the loop it is 



N. 5° E:, at the loop itself it is N. 5° W., with a westerly dip, several 



hard bands of cemented gravel occurring at this point rendering an 



.accurate determination easy. Just past the loop, on the eastern side 



■of the river, and also on the flank of the high escarpment a little further 



down-stream, the beds consist of sand and concretionary bands full 



of shell-remains in excellent state of preservation. This is one of the 



'best localities that I know of for the collection of Tertiary fossils, and 



when thoroughly exhausted will be found to yield a very rich harvest. 



A list of species collected by Dr. Marshall and myself is given later in 



this article, and it will be found to show a marked agreement with those 



collected at the typical Pareora locality, in South Canterbury. 



The structure of the beds becomes at this point somewhat compli- 

 cated, and its unravelment is an interesting problem. On following 

 down the western side of the river below the loop the strike is observed 

 to swing round in the same direction as higher up t!>e river. Just at 

 the mouth of the gorge proper the strike is N. 15° W., with a westerly 

 dip, and just below the Teviotdale Bridge, half a mile further on, it 

 becomes N. 55° W. 



In passing through the gorge the strike has thus swung round through 

 a right angle, and its effect is to be seen in the shape of the ridges of 

 the downs towards Amberley, which are found to circle round with it, 

 the outward slope of the downs being generally towards the dip of the 

 beds. At a point about COO yards above the bridge, at the mouth of 

 a small gully, there has been a marked dislocation of the beds. They 

 have been apparently folded down in an acute isocline, so that the two 

 limbs are approximately parallel; but the beds immediately on either 

 side of it do not appear to be affected, and they do not change their 

 proper level or alter their dip or strike. The disturbance appears to 

 he quite local, and it is not strongly in evidence on the opposite bank 

 of the river. This is the only marked dislocation to be observed through- 

 out the whole length of the gorge, and I have not been able to find any 

 sign of the fault mentioned by Hector (loc. cit.). 



If we now consider the arrangement of the beds on the eastern side 

 of the river, the structure on the western side can be readily understood. 

 Below the loop mentioned previously, on the slope of the high escarp- 

 ment which fronts the river to the west and north-west of the Teviot- 

 dale Station, the beds dip to the south-east, but an open anticline is 

 clearly visible at the point which projects into the river half a mile 

 below. The axis of this anticline is not horizontal, but pitches to 



