THE FINDING OF WOEKABLE COAL. 211 



The sequence of events which we have traced in order to show the 

 relation of the coal measures and the Waiternata beds may be more 

 graphically shown as follows; — Cretaceo-tertiary formation : 1. "Waite- 

 rnata sands and clays. 2. Whangarei or Oamaru limestone. 3. Marly 

 clays and green sands of marine origin. 4. Fireclays and coal, with 

 grits and conglomerates. 5. Basement rock. 



The Waiternata beds occur at the top of the cretaceo-tertiary 

 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 the coal could form at any 

 geological period if the necessaiy conditions existed. We, however, 

 receive little encouragement from this source, as the rapidly alternating 

 character of the Waiternata deposits would tend to show that dynamic 

 forces were at work during this period, causing frequent oscillations of 

 the land, thus preventing the accumulation of sufficient vegetable 

 matter at any period to form workable coal seams. 



Workable seams of coal exist on the flanks of the Hunua Range, 

 and dip in the direction of the Waiternata, but it is doubtful if they 

 reach as far as Auckland ; and, if they do, they would certainly be 

 found at a great depth — probably not much under 800 or 1,000 feet — 

 judging from the thickness of strata which is known to exist between 

 the Waitematas and the coal at other places. 



Auckland stands in the centre of a great syncline or trough, and 

 the depth to be penetrated there would be greater than at any other 

 point. Towards Howick on the one side and Riverhead on the other 

 the depth of strata to be passed through gradually decreases, until on 

 the flanks of the Hunua and Maraetai Ranges the coal crops out on the 

 surface. In the case of the upper reaches of the Waiternata, wherever 

 the old floor or basement rock is found at or near the surface, and 

 whether it is composed of hydraulic limestone or slaty shales, a careful 

 search should be made for indications of coal, for it was on such old 

 floors that the coal vegetatien grew and flourished in older tertiary 

 times. 



If, therefore, there is a probability of coal on the shores of the 

 Waiternata, it will be found in the upper reaches, in the direction of 

 Riverhead, where the edges of the lower members of cretaceo-tertiary 

 formation are upturned against the basement rock. 



STAR CHARTING AND SOME RESULTING 

 DISCOVERIES. 



BY H. C. RUSSELL, GOVERNMENT ASTRONOMER. 

 (Bead at the Meeting of the Boyal Society of New South Wales on July 1st, 1891/ 



Last year I exhibited various photographs of stars and nebula} 

 taken with a portrait camera with a focus of 32 in., and I am now 

 able to show you some of the same objects photographed with the 

 new star camera of 135 in. focus. One could hardly realise the 



