HuTTON. — 0\i the Ages of the N.Z. Coalfields. 385 



accounts for none of the difficulties connected with the idea of 

 three different faunas — of Cretaceous, Eocene, and Miocene 

 facies — belonging to the same period, but living isolated in the 

 same geographical area ; while it introduces new difficulties of 

 its own making. For this recurrence necessitates an emi- 

 gration to some unknown land and a subsequent immigra- 

 tion of the fauna which is very difficult to explain, more 

 especially as the explanation must show why the other two 

 contemporaneous faunas did not accomplish a similar feat. 



Mr. Park says, "All that now remains to place the Cre- 

 taceo-tertiary on a sound basis is to prove that the charac- 

 teristic fauna of the Waihao-greensands horizon occurs below 

 the Amuri limestone, as until this is done there will always 

 remain a doubt as to whether the Waihao and Waipara green- 

 sands represent two distinct formations" (" Eep. Geol. Exp.," 

 1887-88, p. 34). On this I may remark that in my opinion the 

 Waihao fauna has already been found in the Waipara district, in 

 the Mount Brown beds and their equivalents, which lie above 

 the Oamaru series, and therefore far above the Amuri limestone. 

 A list of these fossils will be found in "Trans. N.Z. Inst.," 

 vol. XX., p. 261. It is true that the actual species recorded 

 from the Mount Brown limestones and the Waihao greensands 

 differ much ; but in other localities all the forms are inter- 

 mingled, and the great difference in the mineralogical composi- 

 tion of the rocks at the two localities will probably account 

 for the difference in the species. 



To sum up : the palaeontological objections to the views 

 held by the Geological Survey appear to be insurmountable 

 and impossible to explain. Practically, the Survey gets over 

 these difficulties by ignoring them and classing in one forma- 

 tion all the coals, wdth most of the greensands and limestones, 

 found in the colony. Its opinion is therefore founded on 

 mineral composition ; but the stratigraphical evidence is also 

 said to be favourable, while the palaBontological evidence is 

 supposed to be delusive. Because in many cases the coal is 

 covered by greensands, and these by limestones, it is supposed 

 that all must be equivalents. But this is a sequence of com- 

 mon occurrence in many parts of the world, and is due to the 

 recurrence of similar conditions — that is, to subsidence caus- 

 ing estuarine to be followed by shallow- water, and these by 

 deeper- water, deposits. It is therefore of hardly any weight in 

 correlating detached series of rocks. But in our case the 

 officers of the Survey have confounded together two different 

 kinds of greensands with very different origins. The green- 

 sands at the Waipara (with the Waipara fauna) and those at 

 Curiosity Shop, kc. (with the Oamaru fauna), are glauconitic 

 greensands ; but tliose at Waihao Forks and Hampden (with 

 the Waihao fauna; are volcanic sands — that is, sands derived 

 25 



