Morgan. — Records of Unconformities in 'New Zealand. 5 



has been discussed by Hutton, \vjio, reasoning from the available evidence, 

 decides that the hydraulic limestone is of Upper Oamaru age (30, pp. 380, 

 381, 382), a view that the writer is by no means inclined to endorse. 



6. Komiti (Kumete) Point. — As early as 1877 Hector notes an uncon- 

 formity at Komiti Point between Miocene and Gretaceo-tei*tiary strata 

 (4, p. V of Progress Eeport). In 1881 Cox records that here, and at other 

 localities in the Arapaoa Arm of the Kaipara Harbour, strata containing 

 a varied Tertiary fauna, and referable to the Waitemata Series, rest im- 

 conformably upon chalky clay or hydraidic limestone supposed to belong 

 to the Cretaceo-tertiary Series (8, pp. 17, 33, 37). The next year he renews 

 the statement, and illustrates it by a section (9, pp. 23, 24). In 1886 Park 

 after a brief visit to Komiti Point states that the junction of the Komiti 

 beds and the chalky marls is obscured, but omits to give any definite opinion 

 concerning the unconformity reported by Cox (12, pp. 165-66). In 1887, 

 however, after making a close examination of Komiti Peninsula, he describes 

 a sharp discordance, which he shows in section, between the Komiti beds 

 and blue shaly clays (13, p. 221 ). The lower beds, for no very convincing 

 reasons, he regards as Jurassic (p. 229), and therefore not part of the 

 Cretaceo-tertiary sequence. He also comes to the conclusion that there 

 is only a limited amount of unconformity between the Komiti beds and 

 the hydraulic limestone, and that the obtainable evidence strongly favours 

 a stratigraphical break between the latter rock and the underlying shaly 

 clays (pp. 228, 229). 



The sections and descriptions given by Cox and Park may be accepted 

 as proof of an vmconformity between the Komiti beds of Miocene age and 

 probable Cretaceous strata. Recently (September, 1915) an imconformable 

 junction — doubtless that seen by Cox and Park— has been observed in the 

 south-eastern part of Komiti Peninsula by Mr. J. A. Bartrum and the writer, 

 but owing to adverse weather-conditions was not closely examined. The 

 angular discordance was clear, but apparently not very great. How far 

 there is justification for extending this unconformity to neighbouring 

 areas where less clear sections are observable is open to discussion. Two 

 points of view have been presented, by Park (48, p. 546) and by Marshall 

 (49, p. 319). 



7. Kaipara Flats, Wellsford, &c. — According to Cox, the Cretaceo- 

 tertiary chalk-marl of the Kaipara Flats district is unconformably overlain 

 by Miocene concretionary greensand (8, p. 19). In the same report it is 

 stated that between Wellsford and Mahurangi, greensand unconformably 

 caps hydraulic limestone. In 1914 J. Henderson notes the occurrence of 

 pebbles derived from the hydraulic limestone and associated rocks in the 

 overlying sandstones as evidence of unconformity (60, p. 157). 



8. Mahurangi (Warkivorth) District. — ^ In 1881 Cox gives a section 

 showing strong unconformity at Wilson's (site of lime and cement works) 

 between Cretaceo-tertiary hydraulic limestone and Lower Miocene greensand 

 (8, p. 19). He further states that at Matakana South Head firestone is un- 

 conformably overlain by greensand, &c., and that '' outside the Mahurangi 

 North Head breccia conglomerate occurs containing fragments of slate, 

 quartz, and white granular limestone, which gives additional proof, if it 

 were needed, of the unconformity of these beds to the hydraulic limestone " 

 (p. 29). He also gives a section showing strong unconformity between the 

 hydraulic limestone and Miocene strata west of Little Omaha, near Cape 

 Rodney (p. 31). In 1882 Cox again describes an imconformity in the Mahu- 

 rangi district, shown by horizontal limestones resting on steeply dipping 



