542 Transactions. — Geology. 



Weka Pass Stone at the foot of Mount Brown, in a position 

 that would correspond with that of the supposed lower Cucui- 

 Icea horizon at Mount Donald, Wharekuri, and Kakanui. 



In places where the Mount Brown beds are in contact with 

 the Weka Pass Stone the relation existing between the two 

 formations is not very distinct, the upper formation consisting 

 of soft sandstones naturally conforming more or less com- 

 pletely to the surface of the hard Weka Pass Stone. But the 

 mapping of the rocks puts a different complexion upon the 

 question, and brings out the unconformable relations of the 

 Tertiary to the Cretaceous formation in a very clear manner. 

 Thus, at the 45-mile post the lower, but not the lowest, 

 of the Tertiary beds rests upon the Weka Pass Stone and its 

 associate the Amuri limestone ; and a short distance before 

 reaching the viaduct the same or even lower Tertiary beds 

 rest against the greensands which underlie the Amuri lime- 

 stone. 



Further, the Weka Pass Stone and Amuri limestone are 

 thrown into folds in which the Tertiaries take no part whatever. 



The unconformity between the Mount Brown beds and the 

 Weka Pass Stone was recognised by Sir James Hector* in 

 1868. The former he referred to the Miocene, and the latter 

 to the Waipara formation of Hochstetter. Haastf was also 

 satisfied, in 1870, as to the unconformable relations of the two 

 formations. In reference to this point he wrote, " That the de- 

 nudation of the Weka Pass beds [Weka Pass Stone aud Amuri 

 limestone] had taken place previously to the deposition of the 

 Cucullcea beds No. 11 is well shown in the sections Nos. 6 

 and 7, where the Weka Pass beds stand as isolated islands 

 between the latter, abutting unconformably against them." 



Apart from the stratigraphy, the palaeontological break is 

 complete ; and I do not think that any one will now seriously 

 contend that a formation which contains a Miocene fauna is 

 conformable to a formation containing saurians and other 

 Secondarv forms. 



Waipara Series. 

 (Syn. Waipara Formation, Hochstetter, 1866.) 



The sequence of the rocks belonging to this formation m 

 the Weka Pass and Waipara districts is as follows : — 



1. Weka Pass Stone. 



2. Amuri limestone. 



3. Glauconitic greensands. 



4. Greensands, often argillaceous with saurian boul- 



ders, sometimes covered with a crust of cone- 

 in-cone limestone. 



* Hector, Progress Report, Report of Geol. Survey, 1868-69, p. xii. 

 t Haast, Reports of Geol. Expls., 1870-71, p. 16. 



