248 Transactions. 



The Coal Series. 



Bordering the Hunter's Hills these beds are composed of grits and con- 

 glomerates alternating with coal-seams and followed by sands and 

 sandstones. Farther east the lowest members of the series consist of 

 pipeclays, followed by quartz grits, while the coal itself is represented 

 by a narrow band of carbonaceous clay. 



Usually the conglomerates are " puddingstone " conglomerates, con- 

 sisting of quartz pebbles in an iron-stained matrix. The pebbles have a 

 wide range in size, but ordinarily they are slightly larger than peas. They 

 may also vary much in colour. They may he firmly cemented, forming 

 a coarse sandstone, or they may be crumbly masses of quartz grains. 



The pipeclay, which is of considerable thickness in some places, contains 

 numerous concretions of iron-pyrites and limonite. Sometimes these con- 

 cretions are long and narrow, containing a carbonized substance, which 

 probably represents a piece of wood. The pipeclay has probably been 

 formed by the kaolinization of the feldspar, which, with quartz, is the 

 chief constituent of the greywacke and slates of Mesozoic age. These 

 rocks form the backbone of the country, and the Tertiary series has been 

 deposited on the flanks of the old land. By long-continued denudation 

 these rocks gave up their constituents to form the deposits of the Tertiary 

 series. The coal-beds thin out as they are followed eastward, and are 

 replaced by the other members of the series. 



There are only two important outcrops of coal in the Pareora district, 

 and there is good reason to believe that they occupy different positions 

 in the series. The coal at Otaio lies at the base of the Oamaru series, 

 while the coal at White Rock seems to lie near the top of the Pareora 

 series. The Otaio coal is a good brown coal when obtained from a dry 

 part of the seam, but wet blocks crumble away and leave only a mass of 

 " slack." The beds dip at 60°, so that it would be very difficult to follow 

 the seam. It is also probable that the seam is not continuous over any 

 large area, as it is not found at all in the excellent section of the coal series 

 exposed at Craigmore. Like much of the New Zealand coal, it seems to 

 have been formed in an estuary or bay. This theory is supported by the 

 fact that the grits below the coal contain a small amount of carbonaceous 

 matter, while the coal contains much grit, and the overlying clays again 

 contain pieces of wood. The coal does not seem to have been formed by 

 growth in situ. 



The Lower Sands and Sandstones. 



The grits and clays which alternate with the coal-seams are immediately 

 followed by a succession of sands and sandstones. These vary in colour 

 from grey and green to bright red. Usually the shells in the sands are 

 in poor condition, but those which are found in the sandstones are well 

 preserved. One noteworthy feature of these sands and sandstones is the 

 quantity of carbonaceous matter found in them. In certain layers there 

 are species of simple corals, which are characteristic of this horizon through- 

 out South Canterbury and North Otago. The evidence of the fossils and 

 of the lithological characters of the beds demonstrates that they were 

 formed in comparatively shallow water. 



The Crab-beds and Marls. 



The crab-beds are dark-coloured marls, which grade upwards into grey 

 marls. They are usually brown, but often they are so glauconitic as to 

 deserve the name of " greensands." Their character is very uniform 



