Speight. — Terrace-development of Canterbury Rivers. 41 



where, and their large size renders it highly improbable that they 

 were carried to these places either by ocean-currents or by rivers. 

 In fact, pieces of coal of such size would be quickly reduced to 

 fragments in any of the rivers which cut through the coal- 

 measures. It seems, therefore, highly probable that such masses 

 have come from outcrops of coal in positions which come to the 

 level of the sea-bottom in the localities where they are found. 



Similar occurrences of coal outcropping on the sea-bottom 

 are recorded from the North Sea. If this is really so, then the 

 brown-coal measures of Malvern, Mount Somers, and of other 

 places along the foot of mountains probably extend eastward 

 under the plains in the form of a great syncline, and reappear 

 at a depth of about 150 ft. below sea-level about thirty miles 

 to the eastward of the present coast-line on the scarp of the 

 continental shelf. It is therefore likely that sagging of the 

 crust has gone on in Post-Cretaceous times, but with .periods 

 of depression and elevation, as proved by the marine terraces 

 on Banks Peninsula. If this has gone on recently, it would 

 no doubt affect the form of the terraces ; but I am inclined 

 to think that its effect is not apparent, unless the depression 

 of the land which went on since the glacier maximum is partly 

 due to this cause. The effect of this depression is, without 

 doubt, apparent in the lower courses of the present rivers, as 

 explained previously. 



In conclusion, I have to express my sincere thanks to the 

 following gentlemen for their kindly criticism and generous 

 advice and assistance on many points : Dr. L. Cockayne, Dr. 

 F. W. Hilgendorf, Messrs. E. G. Hogg, E. K. Mulgan, E. M. 

 Laing, T. H. Jackson, Edgar R. Waite, and Edward Dobson, 

 C.E. 



Bibliography. 



The following is a list of papers, &c, which have been referred 

 to in the above, or which have some direct bearing on the sub- 

 ject :— 



Haast, Sir J. von : " Geology of Canterbury and Westland, with a 

 Special Chapter on the Formation of the Canterbury Plains." 



Haast, Sir J. von : " On the Geology of the Canterbury Plains." 

 Trans. N.Z. Inst., vol. vi. 



Thomson, J. T. : "On the Glacial Action and Terrace-formation 

 of South New Zealand." Trans. N.Z. Inst., vol. vi. (This 

 paper draws special attention to the resemblance between 

 the mode of forming a river-fan and that of the plains.) 



Crawford, J. C. : " On the Old Lake System of New Zealand, 

 with Some Observations on the Formation of the Canterburv 

 Plains." Trans. N.Z. Inst., vol. viii. 



