Thomson. — Glacial Action in Otago. 319 



By Ellipse. By Survey, Differences. 



At source 0000 ... 0000 ... 000 



( 5295 ... 6034 ... 739 



At intermediate points -J 5494 ... 6079 ... 585* 



( 6209 ... 6315 ... 106 



At exit to sea ... 6530 ... 6530 ... 000 



It may be remarked here that the points mai-ked with an asterisk being 

 common to both branches, viz., 557 and 585, the near agreement from such 

 Avidely divei-ging data seems to tend to pi'ove a common principle, such as it 

 has been my object to illustrate. 



Having thus endeavoured to follow out the indications of a law that nature 

 pursues, in scooping out the beds of the valleys on the face of the earth, I will 

 now point out one or two examples of extensive abrasions as collateral or 

 confirmatory evidence of some great eroding power acting, which does not 

 exist in this latitude at the present day. Taking a position near to Dunedin, 

 we have the Kaikorai stream, a small mill power issuing from the south end of 

 Flagstaff Hill. This streamlet pursues its course till it falls into the lagoons 

 near Green Island. On examination it will be found to run in a well-defined and 

 permanent bed, within which it would appear contented to remain to eternity — 

 if its once pellucid waters had not been sacriligiously interfered with by wool- 

 scourei'S, tanners, and railway contractors — yet do we see that it has had 

 prepared for its tiny little self a capacious valley of 600 to 6,000 feet in 

 breadth, and 150 to 200 feet in depth. That this valley has been scooped out 

 for the dignity of the little stream is amply proved by the Caversham fossil- 

 bearing limestone of the tertiary period, bounding it almost continuously to 

 the eastward, and underlying it, also showing itself frequent!}' on the westei'n 

 side. The strata of this limestone further give evidence, by its deposition and 

 strike, that it once filled up as level land what is now a spacioiis valley. If 

 the scooping out of this valley be sought to be accounted for by the petty 

 stream now running through it, we would indeed have a monstrous effect from 

 the most puny of causes. The causes must certainly be sought for elsewhere. 

 Again, on the noithern seaboard, we have the immense formations of Oamaru 

 limestones stretching along the coast and up to the mountains. These, again, 

 have been eroded and carried away by forces issuing from the valleys and 

 gorges of the interior, and acting on them in a manner that adlieres to a 

 l)rinciple, viz., the erosions widen with the distances fi'oni the gorges, and 

 creating along the limits of their influence steep and straight lines of escarpment 

 which, at this day, display the interesting cliffs of fossiliferous strata of that 

 district. 



The erosions of the Waitaki, 300 to 500 feet in depth, extend 40 miles into 

 the interior, of | mile in width at the gorge, and 10 miles in width at the sea 

 shore ; of the Kakanui, 20 miles, with a varying width of -^r of a mile to 1 



