Morgan. — Records of Unconformities in New Zealand. 9 



(1a, p. 39, and sections vii, viii,. and xvi). According to his section xv, the 

 Weka Pass stone rests discordantly upon Saurian conglomerate '" one mile 

 above junction of Eden River with Waiau-ua " (Dillon River). 



The sections accompanying Hutton's report of 1877 on the north-east 

 part' of the South Island (3, opposite p. 56) show physical unconformity 

 between Amuri limestone and overlying Tertiary beds at the Conway River, 

 Amuri South Blufi, east head of Kaikoura Peninsula, and Flaxbourne (Ward). 

 In the same volume, however, Hector states that at Kaikoura '' a corrugated 

 concretionary disturbance of the calcareous beds has given rise to an apparent 

 unconformity " (3, p. xi), and that he is unable to satisfy himself " of any 

 stratigraphical break between the Amuri limestone and the overlying Grey 

 Marls " (p. x). McKay, reporting on the Cape Campbell district in the 

 same year, states that the Awatere beds rest with high unconformity on 

 the greensand and Amuri groups (4, p. 186). He also mentions conglome- 

 rates containing boulders both of Awatere and of Amuri rocks (p. 190). 

 Similar conglomerates exposed in the Mead River and elsewhere are described 

 by Hector and McKay as resting discordantly on Grey Marl, Weka Pass 

 stone, or Amuri limestone (12, pp. xvi, xxxiv e< seq., 113 et seq.; sections on 

 pp. 81, 82, 85, 90, 94, 95, 96, 103, &c.). The age of this conglomerate they 

 consider to be post-Miocene. McKay has sections on pages 88 and 89 showing 

 probable unconformity between Tertiary strata and Amuri limestone near 

 Flaxbourne (Ward). On page 83, after discussing the apparent discon- 

 tinuity at Kaikoura Peninsula between the Amuri limestone and the over- 

 lying Grey Marl, he comes to the conclusion that their relations are conform- 

 able. In his Progress Report of 1887 (13, pp. ix et seq.) Hector again mentions 

 that there is no unconformity immediately above the Amuri limestone at 

 Kaikoura, as Hutton supposes. In 1890 McKay again describes what he 

 calls the " Great Post-Miocene Conglomerate " as unconformably younger 

 than the Awatere beds. In several sections he shows it resting discordantly 

 on the Grey Marl (15, pp. 170, 171, 175), and in one as in contact with 

 the Amuri limestone (p. 173 ; see also 12, pp. 81, 82). C. A. Cotton, how- 

 ever, considers that the conglomerate in localities examined by him con- 

 formably succeeds the Grey Marl, and ingeniously accounts for included 

 masses of Grey Marl, Amuri limestone, &c., by supposing that they are 

 derived from a block of adjacent territory which was faulted and uplifted 

 whilst conformable deposition proceeded at its base (57, p. 360). Although 

 Cotton observed several facts supporting his " hypothesis of block-faulting 

 with the restriction that the faulted block alone moved," the very strongest 

 evidence is required in order to establish the correctness of such a startling 

 explanation, which involves a differential elevation " of perhaps as much 

 as 12,000 ft." (57, p. 359). 



Summary. — Since Hector and McKay disagree with Hutton concerning 

 the horizon of a supposed unconformity separating Miocene from older 

 rocks, and since Cotton finds no evidence of a stratigraphical break (other 

 than that involved in block-faulting of part of the area), disconformity 

 must be considered unproved. Hence detailed field-work is necessary to 

 establish the truth or otherwise of any hypothesis.* 



*In December, 1915, the writer visited Kaikoura Peninsula and Amuri Bluff, and 

 there obtained clear evidence of an unconformity between the Amuri limestone proper 

 and an upper baud of limestone corresponding to the Weka Pass stone. At Kaikoura 

 appearances also support the view of a local stratigraphical break or period of non- 

 deposition with slight erosion between the upper limestone and the Grey Marl. 



