300 Transactions. 



The Greymoutli* Coalfield is divided into three sections by faults. The- 

 central Brunner section rests on the southern extension of the Paparoa 

 earth-block, and Point Elizabeth and Blackball sections are downfaulted 

 on either side. The seams are very extensively worked, and analyses 25 

 to 30, Table C, show their composition. 



The Westportf Coalfield is analogous in structure to the Greymouth one. 

 The central Mount Rochfort Coalfield lies on the northern extension of the 

 Paparoa earth-block, and extends as far north as the Mokihinui. The Ori- 

 kaka section, to the east, is downfaulted between the Orikaka and Mawhera 

 faults. The coastal section, to the west, extends from the Punakaiki to north 

 of Westport, and underHes the sea for an unknown distance. The coal 

 of Mount Rochfort section is mined at several points, and the seams range 

 up to 60 ft. in thickness. Analyses 32 to 37, Table C, show the compositions 

 of the coals. 



The Karameai Coalfield extends from the Mokihinui to the Heaphy. 

 Little is known of this field. Analysis 38, Table C, is of a coal from a 7 ft. 

 seam in this field. 



Structurally, the Whakamarama and Taitapu Coalfields may be con- 

 sidered as forming an anticline, § with the Pakawau section as the crown 

 and the Wanganui and Taitapu sections as the limbs of the anticline. This 

 anticline, which plunges to the north, is really the northern section of an 

 elongated dome, formed by the thrusting-up of the Whakamarama earth- 

 block through the coal-measures. This dome was never complete, as the 

 coal-measures never covered the earth-block entirely. The Aorere and 

 Wanganui faults probably grade into flexures in depth and also towards the 

 north. A similar anticlinal structure prevails in the Greymouth and West- 

 port fields, and probably also at the southern end of the Whakamarama 

 earth-block in the Karamea field. The Whakatu field has probably a syn- 

 clinal structure sloping to the north, and this structure has been brought 

 about by the draggiug-up of its edges by faulting. The Kawatiri field is 

 probably boat-shaped for similar reasons ; but the symmetry of the basin 

 has been destroyed by the Motueka and Tutaki faults, which leave the 

 Matiri and Glenroy sections as elevated shelves. The structure of the 

 Oweka field is in the main monoclinal, although, if the Orikaka subfield in 

 the north and the Blackball subfield in the south be regarded as parts of this 

 field, the structure becomes synclinal at these points. 



Composition. 

 It is generally admitted that, omitting cannel coal, &c., all coals have 

 been formed from vegetable matter of initially similar composition. The 

 transformation of this vegetable matter is due to a fractional distillation, 

 and the quality of the resulting coal depends on its relative completeness.. 

 The most generally recognized factors controlling this transformation are 

 time, heat, and crustal movements. 



* Haast : Geologv of W. Nelson, p. 104 et seq. Hector: Geol. Surv., No. 4, 

 pp. 24-27; No. 20, p. xiii ; No. 21, p. xxxviii ; No. 9, p. iv. Cox: No. 10, p. 81. 

 Campbell : No. 11, p. 31. Jlackay : Geologj^ of S.W. Nelson, pp. 57-61. 



t Haast : Loc. cif., j). 113. Hector: Geol. Surv., No. 4, pp. 22-24; No. 9, p. iii ; 

 No. 18, p. 156; No. 21, p. xxxiii. Cox: No. 10, pp. 106-20. Dennisfcon : No. 10. 

 pp. 121-71. Mackav : No. 18, p. 161 et seq. ; No. 21, pp. 76-97. 



X Haast : Loc. at., ]>. 116. Bell : N.Z. Geol. Surv., 2nd Ann. Rep. (u.s.), pp. 7-9„ 

 Webb : Loc. cit., pp. 24-27 ; 3id Ann. Rep. (n.s.), pp. 21. 22. 



§ Hector : Geol. Surv., No. 19, p. x. 



