Marshall. — The Younger Limestones of New Zealand. 89 



A further description of the district was written by McKay.* He 

 correlates the hydraulic limestone with the Amuri limestone in the Cretaceo- 

 tertiary division, but he places the Whangarei limestone in a lower horizon 

 both because of stratigraphical relations in the Whangarei Harbour and 

 because of a clear sequence in a section at Waiomio, where he describes the 

 superposition of the Whangarei as undounted. He classes all the lime- 

 stones in the Cretaceo-tertiary division. 



In the Kaipara district the first description again was written by Cox,t 

 who this time classes the hydraulic limestone as Cretaceo-tertiary. The 

 AVhangarei limestone of the Gibraltar Eocks is said to overlie the Cretaceo- 

 tertiary unconformably, and it is therefore placed in the Upper Eocene. 



ParkJ was the next geologist to describe this area. He makes the 

 hydraulic limestone an equivalent of the Amuri limestone of Cretaceo- 

 tertiary age, and the Whangarei limestone is placed below it conformably 

 and interstratified with the greensands. 



The next geologist to visit the district was McKay, § and in his report 

 he entirely agrees with Park, and also gives a diagram showing the inferior 

 position of the Whangarei limestone to the hydraulic limestone at Waiomio. 

 This opinion has been strengthened by J. A. Bartrum, Lecturer on Geology 

 at the Auckland University College, who assures me in correspondence 

 that the semi-crystalline limestone (Whangarei limestone) lies interstratified 

 in the greensands below the hydraulic limestone near Pahi. Hector and 

 Hutton do not appear to have made any specific references to the stratifi- 

 cation or age of the limestones of this North Auckland district. 



Park's latest statements in regard to these limestones show a consider- 

 able change of view.|| The Whangarei limestone, including the stone of 

 the Gibraltar Rocks, is said to rest conformably on the hydraidic limestone 

 which is still correlated with the Amuri limestone, but both the hydraulic 

 and the Whangarei limestones are now placed in the Cretaceous system. 



2. Cabbage Bay. 



A limestone similar to the Whangarei stone comes from Cabbage Bay, 

 on the Coromandel Peninsula. McKay, in 1885 and 1897, correlated it 

 with the Whangarei limestone of Cretaceo-tertiary age. Park, in 1897, 

 placed it in the Lower Eocene. McLaren (Parliamentary paper, C.-9, 

 "Geology of Coromandel Goldfield"), in 1900, classed it with Hector's 

 Cretaceo-tertiary or Hutton's Oligocene. In Bidl. N.Z. Geol. Sur"v. No. 4. 

 1907, p. 56, Eraser and Adams placed it in the Lower Eocene, and described 

 it as a hard compact limestone consisting largely of bryozoan corals, among 

 which Foraminijera are sparsely scattered. Park, in 1910, placed this 

 limestone as an equivalent of the Ototara stone (Oamaru) of Miocene age. 



3. Kawhia. 



Another similar limestone comes from the Wiwiku Island, Kawhia Har- 

 bour. McKay, in 1883, describes it as a hard subcrystalline limestone of 

 Cretaceo-tertiary age. He says that it lies below the ordinary limestone 

 of this locality. At Morant Island, half a mile away, there is a greensand 



*A. McKay, N.Z. Geol. Rep., 1883-84, pp. 115-28. 

 t S. H. Cox, N.Z. Geol. Rep., 1879-80, p. 17. 

 X J. Park, N.Z. Geol. Rep. 1886-87, pp. 222-28. 

 §A. McKay, N.Z. Geol. Rep. 1887-88, pp. 43-53. 

 II J. Park, " Geology of New Zealand," 1910, p. 96. 



