416 Transactions. 



chief ironsand deposits of southern Taranaki. They are not blown up 

 from the present beaches, but are derived nearly in situ from the Hawera 

 series, and their elevation is largely due to the movements which brought 

 that series into its present position. Few layers of the Hawera series are 

 themselves sufficiently rich in iron minerals to deserve the title of iron-ore, 

 and it is the second sorting, by wind-action, which has produced the con- 

 centration found in the ironsands. 



The Hawera series can be traced continuously all the way on the 

 coast-line between Hawera and Wanganui, except where large graded 

 rivers like the Patea and Waitotara enter the sea by wide valleys. The 

 series is seldom so thick elsewhere as at Hawera, but its composition remains 

 much the same, and the presence of the bored papa beneath it may be seen 

 at a number of points, although shell-beds similar to that at Hawera are 

 not extensively developed. West of Waitotara in the basal bed there are 

 occasional boulders of andesite of a much larger size than those near 

 Hawera. At CastleclifT there is a strong bed of lignite developed. 



The drowned forest so clearly displayed at low water near the 

 mouth of the Waitotara River cannot belong to the Hawera series unless 

 this has been dropped by faulting some 50 ft. in this area, a supposition 

 for which I found no other evidence. Since its formation the Hawera 

 series has undergone elevation to a fairly uniform level, but this forest, 

 together with a similar one which I am informed exists in the Patea River, 

 points to a recent movement of slight depression on this part of th.e coast- 

 line. Park observed that, although the " drift formation " extends inland 

 for many miles, the evidences of submerged forests are never met with 

 more than a mile or two from the present shore-line, and then only in low- 

 lying areas. From this he draws the inference that this forest flourished 

 in a narrow belt of low swampy land adjacent to sea ; but the facts sup- 

 port a different explanation. The forest apparently flourished in the flood- 

 plains of the Waitotara and Patea Rivers, and is only found submerged and 

 partially buried with estuarine mud near the mouths of these rivers, because 

 these were the only areas, with the exception of the sea-beaches, which 

 were carried below high-tide level by the slight movement of depression. 

 On the other hand, the lignite-beds which Park associates with the drowned 

 forests in mode of occurrence are certainly an integral part of the Hawera 

 series. 



The unconformity of the series to the Wanganuian is shown not only 

 by its resting in turn on all the Castlecliffian and Waitotaran beds between 

 Castlecliff and Waitotara, but also by the bored surface existing beneath 

 it, and by the existence of faults which have affected the Waitotara beds 

 prior to their truncation and to the deposition of the Hawera series upon 

 them. A section illustrating this last feature very clearly is exposed on 

 the cliffs west of the mouth of the Waitotara River. 



The mode of formation of the Hawera series seems, from the above 

 observations, to have been much as follows : The Wanganuian beds after 

 their deposition were elevated considerably above sea-level, and also slightly 

 tilted, and were attacked by subaerial and marine erosion. An extensive 

 plain of marine denudation, backed no doubt by sea-cliffs, was thus cut 

 across their upturned edges, and upon this the shell-beds were laid down, 

 followed by sands and layers of mud as marine erosion carried the cliffs 

 landwards. The sands were no doubt in part derived from the coarser 

 material washed out of the Wanganuian beds, and a part of their content 

 of dark minerals may also have been derived from this source, for the 

 papas of Hawera contain volcanic minerals; but the boulders of andesite 



