Canterbury and Westland. 459 



The seam is capped by shales, with smaller seams of brown coal 

 interstratified, and sandy clay marls, overlaid unconformably by post- 

 pliocene alluvium. Section No. Jl, on plate 3, gives the details of this 

 locality. 



On the opposite side, and on the southern banks of the Eiver 

 Ashburton, I discovered another portion of the same basin, consisting 

 of porphyry tufas, shales, and two seams of brown coal, about 4 and 

 5 feet thick, separated by a few feet of inferior coal, or shale. How- 

 ever, as the outcrop was very much decomposed, the two might 

 possibly belong to one seam ; this can easily be ascertained by opening 

 up the ground, which is here also covered by post-pliocene alluvium. 

 The deposits in Alexander Creek, a tributary of the Eiver Stour, are 

 doubtless only a portion of this larger Ashburton-Stour basin; the 

 coal seams are, however, too small and too irregular to be of any 

 practical value. 



In the southern portion of the Province in several localities, brown 

 coal of fair quality has been discovered and is partly worked, but the 

 seams are always irregular and do not extend over a large area 

 wdthout either thinning out or becoming of very inferior quality. I 

 have alluded already to the occurrence of a workable seam at Elephant 

 Hill, on page 310 (section 4, plate No. 5). Similar coal seams are also 

 found at the base of the Oamaru formation in the middle course of the 

 different Waihao branches, but they are as previously pointed out, 

 sometimes of indifferent quality, and often unworkable or difficult of 

 -access. 



Section No. 7, on plate 9, makes us acquainted with the geological 

 features of the Oamaru formation in the middle course of the Opuha, 

 where it leaves the small palaeozoic ranges, forming the easternboundary 

 of the upper Opuha plains. The sequence of the beds is as follows : — 



On the palaeozoic rocks repose — 



No. 1. "White quartzose sands with some harder layers, containing 

 impressions of dicotyledonous leaves, and some pieces of drift- 

 wood changed into lignite. 



No. 2. Seam of brown coal 8 feet thick. It consists of a good dull 

 brown coal, containing a number of layers of glance coal. 



No. 3. Quartzose sands gradually becoming ferruginous. 



No. 4. Ferruginous sand with harder calcareous beds (f ossiferous) . 



No. 5. Grreensands, gradually becoming marly, the upper bed — 



No. 6. Consisting of the characteristic calcareous sandstone, known 

 as the Oamaru or "Weka Pass building stone. 



