Thomsox. — Geology of Middle Waipara and Weka Pass District. 397 



WANGANUIAN. 



The Greta beds have a wide distribution in the neighbouring Lowei 

 Waipara, Upper Waipara, Greta, .and Motunau districts, where the nature 

 of the beds and of the fossils are generally similar to those of the Middle 

 Waipara and Weka Pass. They are also known to occur in the Oaro Valley, 

 near Amuri Bluff. No considerable collections of any extent or receiitly 

 named are available from any of these localities. In 1913 I collected 

 carefully from the Greta beds of the Lower Waipara, but obtained onl}?- 

 twenty-seven species, of which twenty, or 74 per cent., are Recent species. 

 The extinct species were CalUostoma waiparense, Crepidula gregaria, Lutraria 

 solida, Pecten tripJiooki, P. craiofordi, Ostrea arenicola, and 0. nelsoniana (?). 



Owing to the absence of a comprehensive list of Waitotaran fossils 

 from the typical locality, the percentages of records of the various stages 

 shown in Table VI favours correlation of the Greta beds rather with the 

 Castlecliffian than with the Waitotaran, but the presence of such forms 

 as Ostrea ingens suggests that the true correlation is with the Waitotaran. 

 With this the percentage of Recent species, 67 per cent., is also more in 

 accord. Marshall gives 60-70 per cent, for the Waipipi series, which 

 apparently includes the Waitotaran, and 80-90 per cent, for the Castlecliff 

 series. Final decision as to correlation of the Greta beds must be post- 

 poned until lists from the Wanganui-Patea districts are available. 



Only :a small number of species are common to the Greta and Awatere 

 beds, although the latter have usually been correlated with the former 

 Park (1905) obtained forty-two species from the Starborough Creek beds, 

 of which 71 per cent.- were Recent ; from the same beds I obtained fifty- 

 seven species, of which only 51 per cent, were Recent. The two lists 

 combined give seventy-seven species, of which 60 per cent, are Recent. 



Marshall (1919) has suggested that the Greta and Awatere beds may 

 occupy a position intermediate between the Target Gully series (Awamoan, 

 with 30-40 per cent, of Recent species) and the Waipipi series (Waitotaran, 

 with 60-70 per cent, of Recent species). The list of species from the Greta 

 -beds, numbering ninety-five, with 67 per cent., of Recent species, is now 

 sufficient! v extensive to make it very improbable that the suggestion is 

 correct. In the Middle Waipara district the Greta beds follow directly 

 upon the uppermost Mount Brown beds, with only 34 per cent, of Recent 

 species, and the sudden doubling of this percentage gives a strong presump- 

 tion of unconformity. If beds bridging the palaeontological gap can be 

 found in any other part of New Zealand the evidence Jor unconformity will 

 be conclusive. 



In 1913 I pointed out that the Starborough Creek beds of the Awatere 

 Valley were underlain by a great thickness of beds, in the lower parts of 

 which Miocene {i.e., Oamaruian) types such as CucvUaea and Limopsis 

 occurred. The collection from Tatchell's Creek was not in very satisfactory 

 condition, but yielded Ancilla sp., Gardium spafiosium Hutt. ?, C. maorinum 

 Sut. L CJiione meridionalis (Sow.) ?, Cominella lurida (Phil.), Dentalimn soli- 

 dum Hutt., Leda semiteres Hutt. ?, Limopsis aurita (Brocchi), L. catenata Sut., 

 Macidopteplum elegantissimum (Siit.) ?, Mytilus striatus Hutt., Ostrea angasi 

 Sow. ?, Panope orbita (Hutt.), Pecten Imttoni (Park), Struthiolaria cincta 

 Hutt. ?, S. tubercidata Hutt., Turritella symmetrica Hutt. ?, Verconella 

 dilatata (Q. & G.) ?, and Voluta corrugata Hutt. This fauna appears to be 

 characteristically Oamaruian, so that if the beds containing it underlie the 

 Awatere series conformably an intermediate fauna should be found. 



