346 Transactions. 



elevations : Mount Hutt, Mount Alford, Taylor Peak. Mount Somers, and 

 the Clent Hills. This valley has connection with the Rangitata area by 

 means cf the Pudding-stone Valley and by the wide valley extending from 

 Hakatere towards the Potts Eiver. 



The basin of the Rangitata includes the Mesopotamia country, and 

 extends down the river to about eight miles above the Mount Peel Station. 

 Both these basins are in all probability of structural origin, but have been 

 modified extensively by glaciation. They contain numerous remnants of 

 the Tertiary series, which, as originally pointed out h} Ccx, has no relation 

 to the present form of tlie country. They are almost entirely of sands 

 and clays with coal-seams, and only near Lake Heron and at Coal Creek, 

 on the south bank of the Rangitata, are any covering limestones present. 

 The former limestones were classified as Miocene by Cox, and put in the 

 Oamaru formation by Haast, and the latter, judging from its fossils, is of 

 the same age as the Mount Brown limestone of North Canterbury, which 

 may be correlated with the Mount Somers limestone. They are, there- 

 fore, in all probability of later date that the Malvern beds, and represent 

 the gradual extension of the coal conditions over central and southern 

 Canterbury. Remnants of the coal-measures are now found in the Cameron 

 Valley: near Lake Heron ; in the valley of the Smite Creek; near Clent Hills 

 Station; in the valley of the Potts River. The last-mentioned outlier occurs 

 at an elevation of about 3,000 ft. to the north of the ice-swept and moraine- 

 covered downs which stretch from Mount Potts in a south-easterly direction 

 towards the river of the sam° name. The total length of the exposure 

 is about 25 chains, with a maximum breadth of about 7 chains. The beds 

 consist of sands and clays about 200 ft. in thickness, with several seams 

 of brown coal, one of which is 18 ft. thick. They have a general strike 

 in a north-west to south-west direction, with a dip to the south-west at an 

 angle of about 60° ; in some places this is a little natter, but the variation 

 may be due to slip. There is no capping of limestone present, nor was I 

 able to discover any fossils, but from the general circumstances it is evident 

 that the coal belongs to the same series as that at Mount Somers. The 

 beds owe their preservation to having been faulted down and brought into 

 such a position that they have not been subjected to the full intensity of the 

 glacial erosion which other parts of the same valleys have experienced. A 

 similar occurrence exists in the valley of a tributary of the Godley River, 

 in the Mackenzie Country basin, which lies just across the Two Thumb 

 Range, the dividing ridge between the Rangitata and Waitaki basins. In 

 the country immediately to the west of the Lake Stream coal-measures are 

 found up to levels of between 4,000 ft. and 5,000 ft., and these fragmentary 

 occurrences are evidently the remains of a once widely extended sheet. As a 

 rule they do not show much signs of dislocation, though there is no doubt 

 that their position points to certain of them having been faulted down, and 

 their persistence may be due to their having been thus removed from the 

 operation of active erosive agents. Their frequent distribution at high levels, 

 associated with occurrences at lower levels, is strong evidence that the 

 sheet was extended over a surface unlike that now existing, and that the 

 surface has been subject to serious dislocations. The evidence from this 

 locality is strongly in favour of the wide distribution of a mantle of Ter- 

 tiary beds, and is remarkably analogous to the conditions obtaining in 

 Central Otago, where the quartz drifts and associated beds of Tertiary 

 age are found at times depressed in hollows and again in close proximity 

 acting as a capping to the flat-topped schist ridges. 



