408 transactiom. — Geology. 



The lower beds dip 23° N,W., but higher up the river they 

 appear to be horizontal (PL XXV., Section I.), although much 

 disturbed by slips. The plant beds ou the right bank of the 

 river, near the road, dip 65° N.N.W. This high dip is probably 

 due to the fault which has thrown the beds down. On the right 

 bank of the Broken Kiver, where the road crosses, the following 

 section is seen, the rocks dipping 12° S.W. : — 



5. Brown and blue shales, 



4. Grey sand. 



3. Lignite, 2^ feet. 



2. Clay, 3 or'4 feet. 



1. Sands, cuiTent-bedded. 



The sandy beds with StruthioLaria spinosa, etc., were not 

 seen by me in the Thomas River section, although they are 

 well-developed in the Porter River between the two gorges ; it is 

 possible, therefore, that an unconformity may occur below the 

 lignite. However, the lignite is found in the Porter River, 

 between the two gorges, overlying the StrutJiioIaria beds, and I 

 could see no evidence of unconformity ; but the beds are 

 disturbed and the sections obscure. 



An outlier occurs on the Hog's Back, in the north-west corner 

 of the basin, where the beds, resting unconformably on the 

 Waipara System, dip 15° W.S.W. (PL XXV., tig. 2). 



Relation to Oamaru System. — In White-water Creek I have 

 already mentioned that the Pareora System is unconformable to 

 the Oamaru System ; on the north side of Coleridge Creek the 

 Pareora rocks rest on the tufaceous beds of the Oamaru System, 

 the limestone having been entirely denuded away, and in the 

 north part of the basin it rests on the Waipara System. In 

 fact, the unconformity between the Pareora and Oamaru Systems 

 is manifest, and admitted by all. Mr. McKay, however, takes 

 the beds lying on the upper limestone, at the junction of the 

 Thomas with the Porter, as the upper part of the Oamaru 

 System, his reason being that boring molluscs have penetrated 

 some of the shells after the matrix with which they are tilled 

 had consolidated, proving unconformity with the upper beds 

 {I.e., p. 08). But this is not a good reason, as the same thing 

 may be seen in many consolidated beaches at the present day ; 

 and as these particular rocks ai'G very calcareous, they probably 

 consolidated as fast as they were formed. The locaUty is very 

 difficult, indeed dangerous, to get at, and the stratigraphical 

 relations of the rocks cannot be easily examined; but the fossils 

 (localities Nos. 237 and 238 of the Survey) are entirely Pareora, 

 and I therefore include them in that system, as was done by Dr. 

 Hector in 1872. 



Fossils. — As the fossils have been collected from two different 

 horizons, it is better to keep them distinct. The lower horizon 



