Hutton. — The Wanganui System. 341 



and considered that that portion lying between Pohui and the 

 Mangapikopiko ( = Purohutangihia) Range wag an older formation 

 underlying unconformably the limestones of Te Waka and the 

 Purohutangihia. 1 



In 1876, Mr. S. H. Cox considered that the whole of the 

 tertiary rocks from Pohui to Napier formed a single comform- 

 able series, which might possibly be divided into upper and 

 lower." In the same year, Mr. Percy Smith recognised an 

 unconformity near Pohui, between the Mangaharuru sandstone 

 and the overlying beds to the south. 8 



In 1877, Mr. A. McKay gave a section along the Ngaruroro 

 River, 4 which, as well as the geological map of the neighbour- 

 hood, appears to be very correct in all the places examined by 

 me. 



Last January I spent a fortnight in Hawke's Bay, and, 

 accompanied by Mr. A. Hamilton, who had previously sent me 

 many fossils, I examined the section from the Upper Mohaka 

 to Petane, the country about Puketapu, and the valley of the 

 Ngaruroro River, from Hastings to Kikowheru Creek, on Mr. 

 Walter Shrimpton's station of Matapiro. I made the following 

 observations. 



In the Upper Mohaka, where the road from Napier to Lake 

 Taupo crosses the river, the rocks are grey or brown argillaceous 

 sandstone (Fig. 4, a), containing the following fossils : — Struthio- 

 laria tuberculata, S. sulcata, and a species of Cucullaa. They may 

 be referred with safety to the Pareora system. These beds are 

 very thick, more than 800 feet, and are overlain by a thick 

 stratum of hard shelly limestone (b) forming the Te Waka 

 Range, and known as the. Pohui limestone. At the Mohaka 

 the beds dip to the S.E., at an angle of 25°, but at Pohui thev 

 flatten to S.S.E. 10°. 



South of Pohui, we came across a newer series of rocks, 

 resting uncomformably on the denuded surface of the Pohui 

 limestone and the underlying sandstones. This is the com- 

 mencement of the Petane series. It dips here about S.B.E. 15°, 

 and at Petane not more than 6° to the S.S.E., but a slight 

 antichnal fold occurs before reaching Petane (fig. 4). The rocks 

 of the series are as follows, in descending order : — 



5. Two or more thick bands of limestone, with beds of 

 calcareous sand (Petane limestone), sometimes passing 

 into blue clay (/). 



4. Brown sandstones, with a band of conglomerate (e). 



3. Blue clay, known locally as " papa," (d). 



1 " Eep. Geol. Expl.," 1870-71, p. 158. 



3 " Eep. Geol. Expl.," 1874-76, p. 97. 



» " Trans. N.Z. Inst.," vol. ix., p. 565. 



* " Rep. Geol. Expl.," 1876-77, p. 83, and sec. No. 5. 



