296 C. T. Trechmann — Cretaceous Mollusca 



Wilckens, which are Upper Cretaceous but probably still of 

 Senonian age. 



The faunal and stratigraphical details in New Zealand still remain 

 to be worked out, especially in the North Island, but the facts 

 already known point to a north to south as well as to an east to west 

 transgression of late Cretaceous beds, with a further overstep of the 

 Upper Senonian to the south-west across the earlier upper Cretaceous 

 beds beneath them. Mr. H. Woods has recently examined some 

 Cretaceous fossils belonging to the New Zealand Survey collections and 

 concludes that two distinct faunas occur. 1 The older of these occurs 

 at Coverham, in the middle Clarence Valley in the north-east corner 

 of the South Island, and is of approximately Upper Greensand or 

 Gault age. The younger fauna of Upper Senonian age occurs at 

 Amuri Bluff on the north-east coast of the South Island, at Selwyn 

 Rapids, and other localities. 



I understand that only the Lamellibranchs of Selwyn Rapids 

 were examined by Mr. Woods. His work, however, is not published 

 yet. Professor P. Marshall has recently investigated a very interesting 

 and rather extensive fauna which occurs at Wangaloa, on the south- 

 east coast of the South Island south of Dunedin. It is clearly newer 

 than the Upper Senonian faunas above-mentioned, but must, on 

 account of the presence of Pugnelhis, in my opinion, still be referred 

 to the Cretaceous. I should regard it as l)anian or Maestrichtian. 



The object of the present paper is to describe a series of fossils 

 other than the groups already described by Mr. Woods or those at 

 present under description by Professor Marshall, which throw further 

 light on the age and correlation of some of the Cretaceous beds of 

 the South Island of New Zealand. 



All the specimens described were collected by myself, so I can 

 guarantee the accuracy of the localities and horizons. 



The Localities. 



Selivyn Hap ids. 

 This locality is situated at the base of the eastern foothills of the 

 Southern Alps about 36 miles west of Christchurch. The railway 

 station is Grlentunnel, and the outcrop forms a series of rapids 

 in the Selwyn River about a mile from the station. The beds 

 consist of a series of glauconitic greensands more or less concretionary. 

 In the bed of a tributary creek a few hundred yards away there are 

 several enormous spherical concretions 2 5 or 6 feet in diameter 



1 Nature, March 22, 1917, p. 79. 



2 Similar concretions occur at Hampden, in North Otago, in beds apparently 

 of the same age that crop out on the seashore. The concretions are surrounded 

 by a casing of stony material in which the finest cone-in-cone structure I have 

 ever seen is developed. The apices of the cones as a rule are directed towards 

 the centre of the nodule, and the bases of the cones on the outside assume 

 forms that suggest floral structures. The outer skin of the septaria is a few 

 inches thick and is generally loose and detached from the concretion and is 

 easily broken off. This together with the presence of yellow calcite veins 

 which pass in all directions through the septaria suggests that the cone-in-cone 

 structure is connected with a contraction of the inner portion of the septarian 

 concretions. These large septarian nodules are rather sparingly distributed in 



