Park. — On Waitemata Coal. 383 



surface of the coal. It is difficult to look back into these old 

 Eocene times and judge the conditions which prevailed in 

 every isolated nook during the formation of the coal ; but 

 examining the geological records — the fossil life preserved in 

 the rocks — we arrive at the conclusion that in these excep- 

 tional cases the matter which afterwards formed the coal 

 accumulated in narrow, sheltered valleys adjacent to the sea, 

 in places where after its gradual submersion it was not subject 

 to the action of streams or rivers laden with sand or mud or 

 other detritus. 



Again, pursuing the order of events which followed the 

 deposition of the coal, we find that the blue clays and green- 

 sands were followed by shelly and coralline sands which now 

 form the well-known Whangarei, Waipa, Eaglan, Mokau, and 

 Oamaru limestones. These are simply local names for the 

 same limestone which is perhaps one of the most marked, con- 

 stant, and characteristic geological horizons in New Zealand, 

 and seems to form the natural close of the coal-formation. 

 Now, this limestone is followed throughout New Zealand, 

 quite conformably, by a great series or succession of sands 

 and clays, which, in the classification of the New Zea- 

 land Geological Survey, possesses the generic name " Grey 

 Marls," or " Waitemata series." These sands and clays are 

 typically developed on the shores of the Waitemata, which 

 has given its name to the rocks of this period throughout New 

 Zealand. The Waitematas, as seen at Fort Britomart or the 

 Calliope Dock, consist of rapidly-alternating layers of clays 

 and soft sandstones. The presence in these of numerous 

 plant-remains, and sometimes thin irregular streaks of coaly 

 matter, together with the almost entire absence of true marine 

 beds, clearly point to the prevalence of fluviatile conditions 

 during their deposition. 



The sequence of events which we have traced in order to 

 show the relation of the coal-measures and the Waitemata 

 beds may be more graphically shown as follows : — 



Cretaceo-tertiary formation. 



1. Waitemata sands and clays. 



2. Whangarei or Oamaru limestone. 



3. ]\Iarly clays and greensands of marine origin. 



4. Fireclays and coal with grits and conglomerates. 



5. Basement rock. 



The Waitemata beds occur at the top of the Cretaceo-ter- 

 tiary formation, while the coal occurs at the base, the two 

 being separated by two great geological horizons. This in 

 itself might be taken as strong evidence that no coal of a 

 workable nature would be found in the Waitematas ; but we 

 have seen that coal could form at any geological period if the 

 necessary conditions existed. We, however, receive little 



