Dr A. Lord stated that the concentration of Foraminiferida by means of carbon tetrachloride or other heavy liquids is susceptible to error for a number of reasons and counts of such assemblages can introduce serious discrepancies into subsequent statistical studies. Did Mrs Lees examine the heavy residues after the carbon tetrachloride flotations and if so how reliable was the technique in this particular case?
The Author stated that she examined a limited number of residues when first undertaking the flotation technique with the samples. The counts for the residues were added to those for the original flotations, but the differences found were not significant and therefore no further residues were examined. The Start Bay Foraminiferida are fresh and therefore the tests are usually empty. There is a minimal amount of infill material such as pyrite or glauconite, for example, which might prevent floating.
Mr N. J. B. Haward asked whether the author had looked at hydroids in the Recent material.
Mrs Lees replied that no hydroids were found but the substrate in the Bay is mainly sand and is perhaps not as suitable as, say, rock exposures for hydroid attachment.
Professor P. C. Sylvester-Bradley asked whether the microfauna other than Foraminiferida had been examined with a view to the evidence they could give on the environments postulated?
The Author noted that many ostracod species are present but these have not yet been studied.
Dr M. D. Brasier observed that the contradiction between the diversity and triangular plots in terms of