THomson.—Glacial Action in Otago. 323 
most striking are those of the Upper Clutha, near Cromwell; of the Manu- 
herikia, near Alexandra ; and of the Mataura ; but.they are found everywhere 
—from near the mountain tops to the sea shore—having the greatest dimen- 
sions to the most diminutive. Those of the Upper Clutha—a type of the 
former—rise 200 to 300 feet, looking in the distance like a huge wall, and 
attracting the astonished gaze of the beholder. 
These terraces are found to consist of shingle and gravel, bound more or 
less loosely by clay and sand, i.e, where the prior, or tertiary, deposits are not 
yet preserved from abrasion and transport; and this principle universally 
prevails—that the shingle becomes larger as you approach the mountains, and 
smaller as you near the sea. Thus there has been a law of deposit: the 
particles becoming smaller as the transporting power became weaker. Further, 
there has also been a law of deposition and formation, for the terraces incline 
as you close in with the mountains, and they tend to be level as you leave 
them, and only becoming perfectly level on the sea or lake shores. And here 
I may remark that in this part of New Zealand I have missed detecting any 
raised beaches, so frequently spoken of by European geologists, excepting on 
Lake Wakatipu, where those that exist there have been formed by the unusual 
circumstance of the lake once having an outlet by a different direction than 
the present one, and at a higher level, viz, by the valley of the Mataura. 
In illustration of the varying inclination of terraces, I beg to adduce the 
following facts from actual survey. Commencing from the sea shore at the 
Waitaki plain, and following up the lower terrace parallel to the river, we 
found— 
From z to x, Papakaio, in distance n 400 feet, the rise is D feet, or 3:6 pt 1,000. 
x to v. i 0,600 
DE , » а 38 
n vog ” „ 13,400 E ” 50 » 44 ” 
i LQ to В, 2» » 12,700 | ,, » 22 uc ү! 22 
” R to 8, tiens T] 14,300 ” LET 25 I 17 T] 
» 8 09 » 10,300 ,, » 29 » 28 ” 
G to x ,600 » 990 
iti is so evident ‘that ќа саѕез аге — with the terraces of the ўён, 
Taieri, Mataura, and other large rivers, near their mouths, that to detail them 
would be tedious and of no use; we therefore go at once to the interior. On 
the Manuherikia the following are the inclinations of the terrace that abuts 
near Alexandra :— 
From ы to к, Liang bens in distance 12,300 feet, 2 rise is 84 feet, or 6:8 auf 1,000. 
» н og x P “ ues js е wae » ii s: 
4 ae 2 089 5 399 55 
At the Upper Clutha, with one terrace abutting near Cromwell— 
From н to 1, Cromwell, in distance 16,400 feet, the rise is 728 feet, or 44°3 per 1,000. 
And, with another terrace abutting near Wakefield— 
From J to K, Cromwell, in distance 12,400 feet, the rise is 731 feet, or 59:0 per 1,000. 
Thus, there is a law indicated in the nature and formation of these terraces, 
* 
