436 Transactions. — Geology. 



to that made between the Wairoa and Maitai rocks behind 

 Eichmond, ah-eady described."* And on the preceding page, 

 after describing the Eichmond section, which lies a few miles 

 further north, he says, " Perhaps, upon the whole, it may be 

 said that this section does not favour the theory which aims 

 at showing the Wairoa formation to be the younger of the 

 two."f 



Mr. McKay seems unwilling to admit the inferior position 

 of the Wairoa formation no matter how clearly indicated by 

 the stratigraphical evidence, and to get over the difficulty 

 argues that the Trias rocks must be arranged as an "inverted 

 syncline," basing this last supposition on the repetition of the 

 My tikis inoblematicus beds, which he considers must be due 

 to the complete inversion of one side of the supposed syncline. 

 He mentions, however, that the Mytilus bed was the only one 

 which seemed to be repeated, and in this he admits a serious 

 difficultv. An examination of the Mount Heslingtont and 

 Eighty-eight Valley sections shows that the repetition of the 

 Mytihcs bed is due not to inversion, but to the simple circum- 

 stance that there are two distinct horizons of Mytihis, one 

 near the middle of the Trias, and one below the upper granitic 

 conglomerate lying below the Maitai limestone. 



In the section at Sellen's run, a few miles south of the 

 Wairoa Gorge, the Trias and Maitai rocks dip east-south-east 

 at high angles, the former again occupying the inferior 

 position. Writing of this section, Mr. McKay says, " On the 

 ridge east of the limestone at Sutton's " [Sellen's] " these 

 beds" [Wairoa beds] " again dip as though they would pass 

 under the Maitai series," § and in this instance his diagram- 

 matic section along this line correctly shows the Trias rocks 

 dipping conformably below the Maitai limestone as they are 

 actually seen to do. 



The Trias rocks in the section on the north-east side of 

 Well's Creek, in Eighty-eight Valley district, a few miles 

 south of Sellen's line of section, are again seen to dip con- 

 formably below the Maitai formation. Here the whole series 

 is clearly exposed in a regular sequence, dipping to the south- 

 south-oast at angles varying from 50" to 75° or 80°, the in- 

 clination of the beds beconiiug steeper in ascending order to 

 the eastward. 



Speaking of this section, Mr. Mackay says, "Along their 

 junction with the Maitai series the l)eds " [Wairoa beds] 

 " are much crushed and highly indurated, but a short distance 



* Eeps. Gcol. Expl., 1877-78, p. 156. 

 f L.c, p. 155. 



I Mr. McKay, in his reports, erroneously speaks of this hill as Mount 

 Wellington. 



§ Keps. Geol. Expl., 1877-78, p. 157. 



