440 Prof. Garwood — Calcareous Algce. 



surface of the Amuri Limestone as exposed at "VVeka Pass, but to 

 ttie exposures at the Upper AVaipara, where fossils were recently 

 found in the Weka Pass Stone by Dr. Thomson and concerning which 

 I was writing at the time.^ 



The evidence of an unconformity between the Weka Pass Stone 

 and Amuri Limestone at Weka Pass is very meagre, but at the Upper 

 Waipara the corroded, shattered, and brecciated upper surface of the 

 Amuri Limestone certainly favours Uutton's view of unconformity ; 

 and comparing the evidence with that I have seen at the junction of 

 the Eocene and Cretaceous in the section across the Isle of Wight, in 

 the Hampshire Basin, in different parts of the Gallic Basin, in North- 

 West Germany, and in Northern Africa, I have no doubt that 

 European geologists would support Hutton's contention. But the 

 question after all is not dependent on physical conformity or un- 

 conformity, but on the broader platform of palaeontology. So long 

 as a Cretaceous fauna is held to typify a Cretaceous age and a Tertiary 

 fauna a Tertiary age, so long must Hutton's Waipara and Oamaru 

 Systems stand as typical of New Zealand's Cretaceous and Lower 

 Tertiary formations respectively. 



V. — On the Important Part plated by Calcareous Alg^ at certain 

 Geological Horizons, with Special Reference to the Palaeozoic 



EOCKS. 



By Professor E. J. Garwood, M.A., V.P.G.S.^ 



MORE than twenty years ago, whilst engaged in the study of the 

 Lower Carboniferous rocks of Westmorland, I noticed the 

 occurrence of certain small concretionary nodules of very compact 

 texture in the dolomites near the base of the succession in the 

 neighbourhood of Shap. 



Shortly afterwards, when examining the Bernician rocks of 

 Northumberland, I again met with similar compact nodular structures. 

 It was obvious, however, even at that time, that the Northumberland 

 specimens occurred here at a much higher horizon than those which 

 I had observed in Westmorland. 



More recently, whilst studying the. lithological characters of the 

 Lower Carboniferous rocks of the North of England and the Border 

 country, I have been still further impressed by the abundance of 

 these nodular structures at several horizons, and the large tracts of 

 country over which they extend. An examination of these nodules 

 in thin sections showed their obvious organic character, and I was at 

 first inclined to refer them to the Stromatoporoids. Dr. G. J. Hinde, 

 who was kind enough to examine my specimens from the Shap district, 

 reported, however, that they were probably not Stromatoporoids, but 

 Calcareous Algae,' and referred me to the descriptions of Solenopora 

 published by the late Professor Nicholson and Dr. Brown. 



^ "The Supposed Cretaceo-Tertiary Succession of New Zealand," Geol. 

 Mag., November, 1912, pp. 496-7. 



^ Being the substance of his address to the Geological Section of the British 

 Association for the Advancement of Science, Birmingham, 1913 (President of 

 Section C). 



^ See Geol. Mag., 1913, pp. 289-92, PI. X : Dr. G. J. Hinde on Solenopora. 



