2Q8 CAPT. E. W. HiriTOX ox THE GEOLOGICAL POSITIGN 



M'Kay at White-rock station on the east coast of Wellington. At 

 Amuri and Kaikonra this rock contains flints. The WeJca-jxiss 

 Stone is largely developed in the Weka-pass district between the 

 Waipara and the Hurinui, and it forms a large part of Mt. Cass. 

 ^NTorth and south of these rivers it is not certainly knoAvn, but it is 

 generally thought to be the equivalent of the " Ototara Stone " of 

 Oamaru, and of the Cobden limestone of Greymouth. The Grey 

 Marl * extends north from the Waipara through Weka Pass, 

 Motunau, Conway Eiver (?), Amuri Bluff, Kaikoura Peninsula, and 

 perhaps to Cajje Campbell. The Mount-Brown heels are well de- 

 veloped through the Weka-pass district ; but beyond this their ex- 

 tension is uncertain, although no doubt they have equivalents in 

 many parts of Xew Zealand, principally in the south. 



It will thus be seen that the country between the Waipara and 

 the Hurinui is the only district in which all iive rocks can be seen 

 together. The Saurian beds, the AmurL limestone, and the grey 

 marl extend to the north as far as Cook's Straits. But the Weka- 

 pass Stone and the Mount-Brown beds do not follow them, but find 

 their equivalents more in the south. I will now examine the 

 geological relations between them. 



Steatigeaphical Evidence. 



Middle Waijpara. — Dr. Hector reported, in 1869, that " white 

 and 5'ellowish calcareous sandstones \i. e. Mount-Brown beds] rested 

 uuconformably on the lower rocks " t. He did not distinguish be- 

 tween the Grey Marl, the Weka-pass Stone, and the Amuri lime- 

 stone, but considered them all as a "blue-grey marly sandstone 

 sometimes passing into chalk." Subsequently Dr. von Haast 

 divided these rocks into a " Weka-pass Series " [including the 

 Amuri limestone and the Weka-pass Stone], " Cucullsea-beds " \i. e. 

 Grey Marl], and "Mount-Brown Series"!. He agreed with Dr. 

 Hector that an unconformity existed between the Mount-Brown 

 beds and the Grey Marl, and made another unconformity between 

 the Grey Marl and the Weka-pass Stone. In 1873 I distiuguished 

 the Amuri limestone from the Weka-pass Stone, showing that the 

 latter passed at its base into a thin layer of calcareous green sand- 

 stone, which rested on a water-worn surface of the Amuri limestone. 

 I also pointed out that the apparent unconformities were deceptive, 

 and due to a fault (fig. 1) ; and that in reality the Weka-pass Stone, 



* Called " Leda-marls " by Dr. Hector (Trans. N. Z. Inst. vi. (1873), p. 356), 

 and by Mr. M'Kay (Geol. Reports, 1874-76. p. 178). This name has been 

 applied to various rocks in -vridelT separated localities in JS'ew Zealand. Dr. 

 Hector now puts the " Leda-mai-ls " as the equivalent of the Amuri limestone 

 (Geol. Eeports, 1877-78, p. 193), and makes it quite distinct from the grey 

 marls of Weka Pass and Amuri Bluff ; as also does Mr. M'Kay in the Trans. 

 N. Z. Institute, ix. (1876), p. 583. The so-called " Leda-marls" of Eaglan and 

 the Lower Waikato, are probably of about the same age as the Weka-pass Stone. 

 Under these circumstances, I think it is better not to use the name. 



-■■ ' Geological Eeports,' 1868-69, p. 12. 



t 'Geological Eeports,' 1870-71, p. 14 



