Hutton. — The Wanganui System. 343 



side of the Wellington Provincial District, and in Hawke's Bay, 

 several junctious occur. 



1. At Pohui, on the Napier aud Taupo Road, an uncon- 

 formity exists, as was first pointed out by Mr. Percy Smith. 

 (See fig. 4.) According to Mr. Percy Smith, this unconformity 

 is very plain some 12 or 14 miles north of the road, where the 

 lowest beds of the Petane series, called "Middle Papa" by Mr. 

 Smith, dipping at an angle of about 10°, abut against the steep 

 face of the " Maungaharuru sandstone " (Pareora system) at an 

 angle of 29° 30'. "This unconformity," Mr. Smith says, "is 

 a marked feature in viewing the country anywhere near the line 

 of strike of the beds, where the older strata . . _ . are seen 

 dipping at a considerable angle, forming hills which are quite 

 characteristic and different in shape to the Papa hills of the 

 overlying formation." 1 



2. At Napier, the unconformity between the two systems is 

 quite clear ; but this I have described in another paper read this 

 year to the Institute ("On the Geology of Scinde Island "). 



3. Further south, Mr. McKay has shown complete uncon- 

 formity between the two systems at Mount Vernon, near Waipu- 

 kurau. 2 



4. In the East Wairarapa the pliocene beds on the east side 

 of Palliser Bay, which probably belong to the Wanganui system, 

 are said by Mr. McKay to be unconformable to the upper mio- 

 cene rocks (Pareora system) upon which they rest. 3 



5. Again, Dr. Hector has shown that the pliocene (Wanganui) 

 and miocene (Pareora) systems are unconformable at Oneira in 

 Taranaki. 4 



We may, therefore, confidently assert that there is a wide 

 spread unconformity between these two systems, and that they 

 are separated by a period of elevation during which denudation 

 was active. 



Of the 279 species of mollusca known from the Wanganui 

 system, 179 are not found in the Pareora or older rocks. While 

 of 233 species found in the Pareora system, 130 are not found 

 in the Wanganui system, nor in the seas of New Zealand. 5 

 The pakeontological break is, therefore, well marked. The prin- 

 cipal characteristics of the Yv r anganui system are the presence of 

 Trophon, Columbella, Turricula, and Mytilicardia ; as well as the 



1 " Trans. N.Z. Inst.," vol. ix., p. 568, pi. xiii., sec. No. 2. In section 

 So. 1 of this paper, No. 7 (Middle Papa) should evidently be No. 9 (gritty 

 sandstone). No. 7 apparently thins out to the south before reaching Pohui, 

 as mentioned by Mr. Smith on page 569. 



2 " Pep. Geol. Expl.," 1878-79, p. 72. 



3 " Pep. Geol. Exl.," 1878-79, p. 84. 



4 " Rep. Geol. Expl.," 1866-67, p. 2, and section. 



5 The discrepancy between these numbers is owing to three species of 

 recent mollusca occurring in the Pareora system, none of which have as yet 

 been found in the Wanganui system. 



