386 Transactions. — Geology. 



from the denudation of volcanic rocks — and owe their green 

 colour to part of the pyroxene having been changed into chlo- 

 rite. In these cases, therefore, the beds have been correlated by 

 mere superficial colouring, although it is opposed to the palae- 

 ontological evidence, and, as I think, to the stratigraphical 

 evidence also. 



If, now, we dismiss the lithological and accept the palae- 

 ontological evidence, all paleeontological difficulties, of course, 

 vanish, and it merely remains to be seen whether there are any 

 insurmountable stratigraphical difficulties opposed to the view 

 that the three faunas, with their coals, belong to three distinct 

 formations. This question I have discussed in other papers,''' 

 and need not again repeat my ai'guments. I hold that the 

 stratigraphical evidence either agrees with the palaeontological 

 evidence or in some places is neutral, and that it is never 

 actually opposed to it. But stratigraphical evidence depends 

 so much on inference that there is often room for more than 

 one opinion, and arguments are interminable. So far as the 

 Kaipara district is concerned, if Sir James Hector, Mr. Cox, 

 and Mr. Park are right the stratigraphical confirms the palee- 

 ontological evidence; and if Mr. McKay is right it is neutral. 

 Conformity between two series belonging to different periods 

 is not a great nor an unprecedented difficulty. The Cretaceous 

 appears to be conformable to the Jurassic in many parts of 

 England, although really unconformable. The Carboniferous 

 is sometimes conformable, sometimes unconformable, to the 

 Devonian in England and Wales, while in Scotland and Ire- 

 land there is an unconformity in the middle of the Devonian. 

 The Silurian is conformable to the Ordovician in Scotland, 

 but unconformable in Wales and Ireland. The Ordovician is 

 conformable to the Cambrian in Wales, but unconformable in 

 Ireland and Scotland. These examples are sufficient to show 

 that in our case there are no great difficulties in the strati- 

 graphical evidence. Nowhere is the Waipara fauna super- 

 posed on the Oarnaru fauna. Nowhere is the Oamaru fauna 

 actually superposed on the Waihao fauna, although Mr. 

 McKay infers that such is the case at Waihao and in the Wai- 

 reka Valley. 



It seems to me, therefore, evident that the palgeontological 

 evidence can be trusted, and that we have in New Zealand at 

 least three distinct coal-formations, characterized by different 

 faunas. How much these faunas have in common, and, con- 

 sequently, what are the differences in age between them, is 

 another question which has yet to be determined. The correla- 



* "Trans. N.Z. Inst.," vol. iii., p. 244; "Rep. Geol. Exp.," 1872-73, 

 p. 44 ; " Geology of Otago," 1875, p. 50 ; " Quar. Jour. Geol. Soc. of Lon- 

 don," vol. xli., pp. 207, 22G, and 279; "Trans. N.Z. Inst.," vol. xvii., 

 p. 307 ; vol. xix., pp. 406 and 415 ; vol. xx., pp. 257, 2G4. and 267. 



