Hill. — On the Kidnapper and Pohui Conglomerates. 343 



rivers are mostly great shingle-carriers, especially in times of 

 flood, and that the vast deposits of shingle to be met with in 

 the limits of the bay between the Kidnappers and Te Mahia 

 represent some of the products of that carriage within a com- 

 paratively recent period. 



The Tukituki, Mohaka, and Esk Eivers are perhaps the 

 greatest shingle-carriers, and within the basin of each of these 

 I'ivers large deposits of shingle are to be met with. Of the 

 Esk Eiver it may be remarked that its carriage of shingle 

 is not from the mountains, as in the case of the others, 

 but from imniense deposits of shingle-conglomerate between 

 the Kaiwaka and Maiingaharuru Mountains, and to which 

 reference will shortly be made. 



The present river-valleys represent fluvial deposits that 

 have accumulated since the time when the river-system of 

 Hawke'sBay was, in the main, similar to what it now is — ^tliat 

 is, since its slope or drainage-area was generally eastward. 

 But this slope for drainage purposes was not always in this 

 direction, for it can be proved by the most complete evidence 

 derived from the rocks in this same district that the plane of 

 denudation which immediately preceded the. present one, cer- 

 tainly between the parallels of 39° and 40^^, extended from 

 north-east to south-west. And, curiouslj', the evidence to 

 prove this statement is derived from the distribution of 

 shingle-, sand-, and pumice-deposits that are traceable in a 

 great measure in the vicinity of the river-basins already 

 named. 



And now for the proofs : — 



Flanking the slates that form the lower ranges along the 

 western portion of the district there is the remnant of an old 

 limestone deposit. In most places, as I have elsewhere re- 

 marked, this limestone has been washed away, in some cases 

 with portions of the underlying blue clay-marls. But wherever 

 this is the case the area has been reoccupied by shingle, 

 pumice, clays, and allied deposits. 



These beds are clearly exposed in the Makaretu, Tukituki, 

 Waipawa, and Manganuku Rivers, that flow over the Ruata- 

 niwha Plain. No doubt this plain was at one time entirely filled 

 in with these same beds from east to west. Similar beds are 

 traceable to the north-east through Kereru, and thence onward 

 to Pohui. At the Waipukurau, Waipawa, and Maraekakaho 

 gorges remnants of the linking of these beds with the present 

 river-beds are to be found ; and the terrace-gravels of the Geo- 

 logical Department, as seen at Waipawa, Waipukurau, Pata- 

 ngata, and other places, are simply the remnants of a transi- 

 tional period, when the drainage to the south-west, across the 

 Ruataniwha Plains, was dammed back at Norsewood by de- 

 posits froju a rising area to the westward, and breaches were 



