FORAMINIFERA— HERON-ALLEN AND EARLAND. 27 



afforded an opportunity of adumbrating in Section V. of this Introduction a more 

 scientific classification of the Order, especially in regard to the family Lituolidae. 

 The occurrence of such arenaceous isomorphs might liave been reasonably 

 anticipated in the Antarctic. The substitution of an adventitious test for one 

 composed of calcium carbonate is no doubt a physiological process due to the 

 low temperature of the animal's environment. It has long been observed that 

 tropical organisms secrete calcium carbonate in great abundance, while benthic 

 and Arctic organisms are characterised by thm, delicate shells, and the experiments 

 of Murray and Irvine proved that the reactions involved in the fixation of 

 CaCOg were retarded by cold and accelerated by heat. (But see p. 34.) 



The fossil or sub-fossil material received from Stations 2, 3, and 6 presents 

 some difficulty. The distinctive nature of the material does not appear to have 

 been recognised when it was obtained from the dredge, and no records were made 

 of its occurrence and relative abundance. The material from these Stations 

 therefore consists of : (1) recent muds and sands easily recognisable as such ; 

 (2) more or less disintegrated lumps of the deposit in question ; (3) a mixture 

 of the two in which it is not always possible to discriminate between the 

 constituents. 



Some of the harder lumps of this deposit have been submitted to various 

 authorities who, as a rule, decline to commit themselves to any definite statement 

 as to its age. The general consensus of opinion is, that the deposit is probably 

 of no great antiquity but represents a recent sea-bottom consolidated by the 

 solution and .subsequent re-deposition of CaCOg in sea water. 



Mr. A. W. Waters, on the other hand, after preparation and exammation of 

 the material, is inclined to attribute a Tertiary origin to the deposit, on the 

 strength of the occurrence therein of certain Polyzoa {Cellar ia angustiloba, 

 Entalophora verticillafa, Cellepora fossa) known only as typical Tertiary fossils. 

 He compares the Polyzoan fauna with certam beds hi Victoria attributed to the 

 Miocene or Oligocene. 



The matter lies outside our province and can only be settled by a further 

 examination of suitable material. We will only observe that if the deposit is of 

 the age suggested, we should have anticipated the occurrence of similarly typical 

 Tertiary Forammifera. With the exception of a single specunen of Nummulites 

 variolarius found at an early stage of our work, anterior to the receipt of 

 Mr. Waters's report, no distinctive fossils occur among the Foraminifera.* The species 

 listed from the hard deposit are to all intents and purposes identical with the 

 recent forms at the same Stations, and any differences are prmcipally due to 

 development, which is usually more noticeable in the fossil than in the recent 



* We had rejected this Nummulite without hesitation as due to extraneous circumstances, althougli 

 we felt that all possible precautions had been adopted in cleaning the material, but in view of Mr. Waters's 

 report its occurrence, if accepted, has obviously a considerable value as evidence in support of his theory. 



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