6 TraiiKcicfions. 



clialk-marl and hydraulic limestone (9, p. 24). Two years later McKay 

 confirms the existence of a pre-Miocene imconformity near Warkworth, 

 and gives a section similar to Cox's illustrating the unconformity at Wilson's 

 (11, pp. 105, 106). In 1914 J. Henderson reports unconformity between 

 probable Miocene and Cretaceous rocks, in the following terms : " Although 

 the relationships of the hydraulic limestone and the green sandstones are 

 nowhere within the district shown clearly in section, the discordance of 

 the formations is proved by the numerous coarser bands which occur in the 

 sandstones, containing waterworn pebbles of hydraulic limestone, calcareous 

 marl, and, rarely, carbonaceous shale derived from the denudation of the 

 hydraulic limestone and associated beds " (60, p. 157). 



9. Wade District. — 'In 1884 McKay reports that on the banks of the 

 Orewa River " Cretaceo-tertiary rocks are unconformably overlain by soft 

 dirty greensandstones " (11, p. 104). Some years later Park confirms the 

 presence of an unconformity in this locality by a section given without 

 anv comment (13, p. 226). This, however, he supplies in 1911 and 1912 

 (48, p. 545, and 50, p. 493). 



Summary of North Auckland Data. — -Cox, McKay, and Park agree in 

 observing angular unconformity between Miocene and Cretaceo-tertiary 

 strata, and show it as very sharp in several sections — -for example, at Komiti 

 Point (Cox and Park), at Wilson's near Warkworth (Cox and McKay), 

 and Orewa River (McKay and Park). The existence of a basal Miocene 

 conglomerate containing pebbles derived from the hydraulic limestone and 

 other rocks of probable Cretaceous age is demonstrated by Hector, Cox, 

 and Henderson. Again the wide overlap of the Miocene strata on the pre- 

 Cretaceous (Trias-Jura) rocks here as elsewhere in New Zealand is highly 

 significant. As a whole, the evidence for unconformity between Miocene 

 and all older rocks appears to be conclusive. Cox and Park agree in finding 

 an unconformity between the Whangarei limestone and the hydraulic or 

 chalky limestone, but the supporting evidence is unsatisfactory, and at a 

 later date Park takes quite a different view (45, p. 95). 



II. Waitemata, Drury, and Waikato Districts. 



In 1871 Hutton contends that the Tertiary rocks south of Auckland 

 exhibit two unconformities — one between the brown-coal measures of Eocene 

 age and the Aotea Series of Oligocene age, the other between the Aotea 

 rocks and the Waitemata Series of Upper Miocene age (19 ; and see also 22). 

 In 1882 Cox reports a probable unconformity near Howick (9, pp. 95, 96). 

 In 1884 McKay, supported by Hector, suggests an unconformity at the 

 horizon of the Parnell grit (11, pp. 106, xviii ; 12, p. xxxviii) — -that is, 

 in the Waitemata Series — -and assigns the beds below the grit to the 

 Cretaceo-tertiary system. Park rejects the supposed unconformity at the 

 Parnell-grit horizon, but believes that there is one at the base of the Waite- 

 mata Series (12, p. 158 ; 31, pp. 391-99). In 1892, however, he maintains 

 that there is conformity to the base of the Cretaceo-tertiary (32, p. 381). 

 Subsequent papers by E. K. Mulgan (37) and C. E. Fox (38) deal very hardly 

 with the Parnell-grit unconformity, an attitude which is in agreement with 

 the writer's observations, though it must be admitted that at St. George's 

 B..y there is a minor local unconformity, indicated by the wedging-out of 

 several feet of the beds underlying the grit. Neither Mulgan nor Fox seems 

 to support unconformity in any part of the Tertiary sequence as developed 

 near Auckland, and Clarke's paper of 1905 (40), together with his latest 



