McKay. — On the Age of the Napier Limestone. 373 



observed that the next rocks seen on the road-line, to the 

 S.E. of the disappearance of the Upper Pohui limestone, were 

 light grey sandy beds, very much resembling those seen to the 

 N.W. of the Lower Pohui limestone on the fall from the Saddle 

 into the Mohaka Valley, and these might be brought into this 

 position by a fault or unconformity ; but, were this so, the over- 

 lying brown sands and conglomerate would yet have to show 

 evidence of unconformity, and I could discover none. 



Further to the E. and S.E. the section has already been 

 described by previous observers, and I need not here detail it. 



Grey and brown sands and coarse sandstone conglomerates, 

 pupa rock, and tufaceous sands, form a great series of strata 

 before reaching the overlying shelly-limestones of Petane and 

 the coast range to the N.E. of the Lower Esk. Between Pohui 

 Lake and the coast there may be 2,000, 3,000, or even 4,000 feet 

 of strata ; its exact measure is not at present of importance, it 

 being admitted on all hands that collectively there is a great 

 thickness of strata, amounting to some thousands of feet. This, 

 in some way, we have to consider represented in Scinde Island, 

 and by not more than some 120 to 150 feet of strata. This is 

 possible, but, considering the distance between the Esk Valley 

 and Napier, barely probable. 



Next we have to consider that the section from Puketapu, on 

 the Tutaekuri River, back to the S.W. continuation of the Pohui 

 limestone, shows no diminished thickness of the beds overlying 

 the latter and underlying the Petane limestone, rendering it yet 

 less probable that this great series can be represented a few 

 miles off by so small a thickness as that of their supposed 

 representatives in Scinde Island. Farther to the S.W., along 

 the Ngaruroro Kiver, from the limestone hills on the western 

 border of the Ahuriri Plain to the lower end of the Ngaruroro 

 Gorge, a yet greater thickness of these beds is developed ; and 

 let any one look from the offing in Hawke's Bay at the immense 

 development of conglomerates, sands, and clays, that between 

 Cape Kidnappers and the mouth of the Tukituki are present, and 

 then consider that these must be fully represented in Scinde 

 Island — if we are to regard the upper shelly limestones there 

 the same as that found on the mainland at Petane ; or, as an 

 alternative, the lower limestones the same as the Te Aute lime- 

 stone. And, in spite of liberal allowance in the way of thickening 

 and thinning of the strata, the reasonable probabilities of the case 

 will be, with most observers, that either the Petane limestones 

 are not present, or, that the Te Aute limestones are absent. 

 There is, however, a third possibility : but this has never yet 

 suggested itself to any observer of the geology of the district, and 

 I dare say will not now be entertained. This is : there may be 

 a double unconformity in Scinde Island. Firstly, between the 

 lower or supposed Te Aute limestones of Hutton ; and, secondly, 



