182 Transactions. 



fossils are either found in higher beds or are Recent. The horizon of these 

 tuffs is doubtful, but the association of these calcareous tuffs with chalky- 

 clays and marls is similar to the beds near the base of the Ototaran in the 

 section exposed on the right bank of the Kakanui River (p. 57, fig. 19). 

 The writer has also observed these marly beds and tuSs near the base of 

 the limestone in the old quarry at Fortification Hill, near the village of 

 Alma. 



VI. Summary and Conclusion. 



It has been contended that the sequence and subdivision of the 

 Tertiary beds of North Otago as detailed in Bulletin No. 20 requires 

 certain modifications, and the following conclusions have been reached 

 by the writer : — 



(1.) Park's Lower Hutchinsonian is the true Hutchinsonian of Thomson, 

 and is characterized by the fossils Pachymagas parki (Hutt.), Aetheia gauUeri 

 (Morris), Terebratulina suessi (Hutt.), Isis dactyla Ten. -Woods, and Mopsea 

 hamiltoni (Thomson). 



(2.) No evidence has been brought forward in the bulletin for the 

 establishment of an Upper Hutchinsonian horizon in the area lying between 

 All Day Bay and Upper Target Gully. The beds referred to this horizon 

 are Awamoan, and lie immediately on the " parki " greensands. 



(3.) The highest beds present in the Landon Creek area are the " parki " 

 greensands, and in the Flume Creek area the ''''Isis'' greensands, which 

 constitute Park's Lower Hutchinsonian ; there cannot, therefore, be an 

 Upper Hutchinsonian horizon in these localities. 



(4.) No evidence is presented in Bulletin No. 20 to show that the 

 Ototaran limestone in the Oamaru and Papakaio districts correlates with 

 the beds below the limestone in the Waitaki Valley. Both limestones 

 contain several brachiopods which are restricted to the Ototaran of the 

 typical Oamaru district, and must be classed as Ototaran. 



(5.) The nature of the limestone (polyzoan limestone) interbedded with 

 the tuffs beneath the lower pillow-lava at Boatman's Harbour and Shirley 

 Creek, and the brachiopods obtained from these bands, strongly suggest 

 that their age is Ototaran, not Waiarekan. 



(6.) The occurrence of Awamoan fossils in the beds (Otiake beds) above 

 the limestone of the Waitaki Valley, and the fact that the Awamoan and 

 Hutchinsonian are " part and parcel of the same series," as Hutton, 

 McKay, and Park have asserted, further strengthens the argument that 

 this limestone is Ototaran. 



(7.) Nevertheless, the brachiopod faima of the greensands in the Oamaru 

 coastal district enables a clear line of demarcation to be drawn in that 

 area between the Hutchinsonian and Awamoan. 



Bibliography. 



Hutton, F. W., 1887. Note on the Geology of the VaUey of the Waihao, in South 



Canterbury, Trans. N.Z. Inst, vol. 19, pp. 430-33. 

 Pap.k, J., 1905. On the Marine Tertiaries of Otago and South Canterbury, Trans. 



N.Z. Inst, vol. 37, pp. 489-551. 

 Thomson, J. A., 1915. Classification and Correlation of the Tertiary Rocks, 8th Ann. 



Rep. N.Z. Geol. Surv., pp. 123-24. 



1916. On Stage Names applicable to the Divisions of the Tertiary in New Zea- 



land, Trans. N.Z. Inst., vol. 48, pp. 28-40. 

 Uttley, G. H., 1916. Geology of the Neighbourhood of Kakanui, Trans. N.Z. Inst., 

 vol. 48, pp. 19-27. 



1918a. The Volcanic Rocks of Oamaru, Trans. N.Z. Inst., vol. 50, pp. 106-17. 



1918b. Geology of the Oamaru-Papakaio District, Trans. N.Z. Inst., vol. 50, 



pp. 118-24. 



