Pake. — On the Amount of Coal in Neio Zealand. 327 



surfaces, the seams uecessarily partake of all the nTegularities 

 of the land, and are consequently subject to great variations 

 of thickness along the line of outcrop. It is also noticeable 

 that Yv'here the land is steep the seams thin out rapidly to the 



dip. 



It is a remarkable fact that, although the workable coals of 

 New Zealand are all of the same age, they differ widely in 

 their mineral characters and composition : for example, those 

 of Otago are hydrated brown varieties, sometimes little better 

 than lignites, while those of the west coast of the South Island 

 are anhydrous or bituminous coals, mostly of fine quality, and 

 in some respects superior to the coals from New South Wales. 

 It should be stated, however, that the different varieties shade 

 into each other : thus we have brown coals which exhibit an 

 approach to semi-bituminous coals, which in their turn merge 

 into true bituminous or caking-coals. 



It would be difficult to define a dynamic agency competent 

 to produce the metamorphism of the coals of the Grey and 

 Buller coalfields, and at the same time so exclusive as to 

 restrict its operations to these areas. 



When this interesting question receives more attention, it 

 will, I think, be found that the quality of the coal is largely 

 influenced by the character of the enclosing strata: thus, 

 when the measures are loose and porous the decomposition of 

 the vegetable matter will probably result in the formation of 

 lignites or hydrous brown coals, such as those of Otago ; 

 when greensands of a less pervious nature, a better class of 

 coal wall be formed, of which examples may be found at the 

 Mokau, Waipu, Whangarei, and Kawakawa coalfields ; and 

 when heavy deposits of impervious fireclays, the result will be 

 bituminous coals. 



As the result of a large number of analyses in the Colo- 

 nial Laboratory, Dr. Hector in 1872 classified the coals of 

 New Zealand as follows : — 



I. Hydrous (coal containing from 6 to 20 per cent, of per- 



manent water) — 



a. Lignite. 



b. Brown coal. 



c. Pitch-coal. 



II. Anhydrous (coal containing less than 6 per cent, of 



water) — 



a. Glance-coal. 



b. Semi-bituminous coal. 



c. Bituminous coal. 



The workable coals come under three principal divisions — 

 namely, (1) brown coal, (2) pitch-coal, and (3) bituminous 

 coal. These varieties are distributed in what may be termed 



