HuTTON. — Geology of the Trelissirk Basin. 407 



pointed out by Mr. McKay. At White-water Creek the Amuri 

 limestone bad been denuded down to a few feet before the 

 Oamaru System was deposited ; and in the lower part of Cole- 

 ridge Creek the Oamaru System rests on the marl, the Amuri 

 limestone having been entirely removed, although it still retains 

 a thickness of between 200 and 300 feet at each end of the basin. 

 In the upper part of Coleridge Creek an unconformity can also 

 be made out, the Waipara System striking N.W., and the 

 Oamaru System, in contact with it, W.S.W. The unconformity 

 is therefore well marked. 



Paheora System. 



This system rests on paleozoic rocks along the west margin 

 of the basin, and extends eastward to the Oamaru System. 

 More to the north it rests on the Waipara System. It attains 

 its greatest elevation (3,390 feet) at the Hog's Back, while in the 

 southern part of the basin it does not reach to 3,000 feet. 



The following is the section, in descending order, seen in an 

 affluent of White-water Creek from the north. (PL XXV., 

 Section III.) 



Feet. 



7. Blue shales (plant beds) ... ... ... 150 



6. Soft grey sandstone, current-bedded ... ... 200 



5. Grey sandstone, or sand, Avith layers of broken 



shells, Struthiolaria spinosa, etc. ... ... 80 



4. Sandy clay full of Lamehibranchs ... ... 2 



3. Grey sandstone, with shells and concretionary 



layers ... ... ... ... ... 15 



2. bandy clay, full of Lamellibranchs ... ... 3 



1. Grey calcareous sandstone, with shells ... 15 



No. 1 rests upon the denuded surface of the limestone of the 

 Oamaru System (Weka Pass stone), which dips 15° W.S.W., 

 while the Pareora System dips 10° W.N.W. Further up the 

 creek the dip of the Pareora System remains the same in direc- 

 tion, but increases to 25° in No. 7. 



In Moth Creek the beds are obscure, but they consist of blue 

 sandy clays with marine shells, probably representing No. 6 of 

 the White-water Creek section. In the Thomas Eiver, from the 

 road crossing downwaids, the following are seen : — 



6. Dark grey clay and shales, with plant remains. 



5. Pale grey-yellowish sands, and thin seams of shale, 



with plants. 



4. Grey sandy clays and shale. 



8. Lignite. 



2. Grey sandstone, full of Lamelhbrauchs. 



1 . Grey sandstone, current-bedded — 200 feet. 



