456 Geology of 



both together forming the upper deposits of the whole district. la- 

 the upper portion of the valley no large seams are visible, and only 

 three small ones of 1, 3, and 5 inches appear between the shales. 



Section No 3 on plate No 4 gives the details of this interesting and 

 instructive section. 



In the so called chasm on the left bank of the Rakaia gorge, 

 another series of coal seams (section No 8 on plate 3) is exposed,, 

 which will be of some value in future years. The terrace consists here 

 in descending order of about 



150 feet Alluvium ... ... bluish tint 



30 ,, „ .... ... reddish tint 



100 „ ., ... ... bluish tint 



consisting throughout of river sand and river shingle. Below the last 

 mentioned deposit the first visible bed consists of ferruginous shales- 

 followed, in ascending order, by 



Fine Brown Coal (Pitchcoal) 



Conglomerate consisting mostly of pebbles of 

 Quartziferous Porphyry ... 



Coal 



Grey shale 



Coal 



Shale, only exposed in part ... 

 The last seam consists of a fine hard pitch coal interstratified with 

 numerous small layers of glance coal. 



In the more northern portions of the province, coal seams of 

 economic value are of rare occurrence. There is a seam near the 

 source of the Motanau, 4 feet thick, which one day may be useful to 

 the district. Another seam of similar thickness is exposed near the 

 source of a creek falling a few miles north of the mouth of the Motanau 

 into the sea, but it is difficult of access. In the Waipara and its tribu- 

 taries the beds corresponding with the coal seams of the Malvern 

 Hills consist, with the exception of a seam in Boby's Creek, only of 

 a very shaly lignite, and of inconsiderable thickness. Of the outliers 

 containing brown coal of good quality, those behind Big Ben and at 

 Craigieburn might also here be mentioned. 



ft. 



in. 



5 



2 



6 







1 



9 







3 



12 



6 



Oa^IAEU FoEMATIOy. 



As previously stated, there are a number of coal seams of some- 

 economic value in the Oamaru formation, stretching from the northern 



