PRE.^IDEiSrr's ADDRESS — SECTION 93 



are recent. Th© presence of Gilhertia, Volutoderma, Trigonia, 

 and Dxiroloma, are indicative of considerable age. Two forms 

 only are common to Hampden and Wangaloa, and Marshall is of 

 the opinion that the faunal difference is in all probability due to 

 difference of station, rather than difference of age. Of the same 

 age again may be the fossiliferous greensands, that overlie the 

 basal coal-bearing beds in Waihao district in South Canterbury, 

 50 miles north of Hampden (Hector 1891, Park 1905), but further 

 work here is desirable. In the Oamaru district, however, th© coal- 

 measures are directly overlain by marine tuffs termed the 

 Waiarekan series, from which 221 species of moll sea are 

 known, of which twenty-five per cent, are recent. Park (1918i 

 and Mar=;hall (1919) recognised a Icwer and upper stage in this 

 seri-^, but as the fossils ol the former ar:i all casts, it seems wisest 

 to disregard them for the present, though it may be possible to 

 confirm th© subdivision at a later date. This series contains ^ 

 band of diatom a ceous earth in which 283 species and varieties of 

 diatoms (Grove and Sturt, 1S86-7), and 110 species of siliceous 

 sponges (Hinde and Holmes, 1890) have been found. According 

 to Park (^1918) there is an extensive development of ellipsoidal 

 basaltic flow within this series, though Uttley (1920) believes that 

 these should be placed in the succeeding formation. 



This formation is the Oamaru polj'zoan limestone which is 

 divided into two portions in the coastal districts by a large inter- 

 posed wedgre of coarse breccia-tuff, and, according toi Uttley, by 

 the ellipsoidal or pillow lavas. It contains, besides the pclyzoa, a 

 dozen species of Foraminfera, four ostracods, a large echinoid 

 (Pericosmns coni/jjressus), and locally an immense abundance of a 

 few sub-genera of Terebratulidae. Other mollusca, which are of 

 the same type as those in the sediments above and below the lime- 

 stone, are present in the interstratified tuffs. This is the Ototaran 

 stag© of Thomson. Following this is a very continuous band of 

 greensand characterized by a great abundance of the brachiopod 

 l^achi/migas jmrln, together with other organizms, nearly a hun- 

 dred species of which have been found. This forms the Hutchin- 

 sonian otage. It is fcllowed by the most richly fossiliferous as 

 well as the highest subdivision, the Awamoan stage, of sands and 

 clayS; in which 336 species of molluscs have been recorded, of 

 which thirty-four per cent, are Recent. "It would be prema- 

 ture," says Tbomson (1920), "to assume that there had been a 

 sudden introduction of new forms in this Awamoan stage, although 

 that is the actual suggestion of the lists." This clores the Tertiary 

 sequence in the Oamaru district, and Pleistocene gravels lie un- 

 conformably on the formation mentioned The material upon which 

 the faunal lists are based has been greatly extended in th© past 

 decade by th© collecting of Marshal], Park, Thomson, and Uttley, 



