404 Transactions. 



geologists. We believe that this occurrence of a younger fauna in the 

 basement beds in some districts than in others is due simply to overlapping. 

 This, however, is difficult to prove, for earth-movements that have occurred 

 since the deposition of these rocks have greatly altered the relative levels 

 of different portions of the country, so that it is now difficult, if not im- 

 possible, to restore the early Cainozoic relief.^ 



The disposition of the Cainozoic series shows quite clearly that the 

 relief was then highly varied, and, if that was the case, overlapping must 

 have taken place to a great extent in a series which in some places was 

 3,000 ft., in others perhaps 10,000 ft. thick, and deposited during a move- 

 ment of depression that was more rapid than the rate of deposition. 



This creates great difficulties in the way of all attempts to correlate the 

 members of the rock-series as developed in different districts, for the relief 

 of the land before depression had been so great, and the movement of 

 depression was so much more rapid than deposition, that limestones and 

 conglomerates were in the middle of the period being deposited within a 

 comparatively short distance from one another. This difficulty is par- 

 ticularly marked because the lowest rocks are usually unfossiliferous. \ 



While great difficulties arise for these reasons in all attempts to correlate 

 the basal conglomerates, there is not the same trouble in correlating other 

 members of the series. This is particularly true of the limestones. The 

 nature of this member of the series proves that it was deposited at the time 

 of maximum depression, when some of the areas at least were covered by 

 deep water, and the area of the land-surface was so decreased that little 

 sediment was derived from it, and in many places calcareous conglomerates 

 were deposited on the very shore-line. The differences in the limestone in 

 different localities have already been described, but it is necessary to state 

 that the variations are found in detail only. The fact that where a com- 

 plete series is developed the limestone always occupies the same position 

 strongly supports the correlation of the limestones throughout the series.* 

 This is the correlation adopted by Hector, and almost by Hutton, except 

 that he placed the Aniuri limestone in a lower unconformable series. It 

 is wholly opposed to the classification of Park, who correlates the great 

 limestone formation throughout the country with the calcareous knobbly 

 conglomerate of Mount Brown. From this we wholly differ, for the palaeon- 

 tological evidence upon which it is based is far from complete, and can be 

 interpreted in very different ways. The correlation is mainly based upon 

 the resemblance between the fossils collected by him at Mount Donald 

 (Mount Brown beds) and those of the Black Point beds, which are lower 

 than the limestone in this locality ; and, again, the similarity of fossils in 

 these beds to those in the Awamoa beds, which lie over the Oamaru stone, 

 appears to be the reason for suggesting that a second bed of limestone — 

 Waitaki stone — should rest on the Awamoa beds. It is also asserted that 

 McKay and Hector always agreed that the Pareora fauna lay below the 

 Waitaki stone.t This appears to be an error, for in Hector's Handbook 

 the Pareora and Awamoa beds are placed in the Miocene, the Hutchinson 

 Quarry beds in the Eocene, and the Ototara series (Oamaru and Waitaki 

 stone of Park) in the Cretaceo-tertiary. When this similarity of fossil 



* See T. C. Chamberlain : " Diastrophisni as the Ultimate Basis of Correlation 

 ('• Journal of Geology," vol. 17, 1009, p. 085). 

 t Trans. N.Z. Inst., vol. 37, p. 504, 1905. 



